[Compiled Synth-DIY on topic "ASM-1" through 11/96] >From owner-synth-diy Tue Apr 23 17:12:59 1996 Date: Tue, 23 Apr 96 10:10:50 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Circuit Board Update 4/23 Hi DIY list, Well I got the prototype of my new circuit board up and running, at least on the test bench. All the little prototype tweaks have been made and I'll be ready to go out for the new film as soon as I can gerber up the artwork file. The thing is called the "ASM-1", for "Analog Synthesizer Module One". The frequency range of the VCO's are from below 1 Hz to above 125 Khz (wow!). I had not-so-good luck with this VCO design last year on the breadboard, but seems like I had some construction problems at the time (solder flux contamination), because these suckers work great. I *had* to give it another chance because in Electronotes it says that of all the designs that have ever graced those pages, this VCO is the most stable and accurate. The parts count is low and the hardest part to find is the 2N4856 FET, which is over-the-counter at the local electronics store (NTE part number = NTE466). The exponential converter uses a pair of NPN's, so that means that a couple of hand-matched 2N3904's should work fine. That's what I'm using right now, and they're not even matched. I've listened to the filter and it's your typical high-quality multi-mode sound. It's another "best of Electronotes" design so it should be a real work-horse. The ADSR's, the VCA's, the noise source, and the LFO all appear to be working fine. I've drawn up the schematics and the suggested panel connections. next I'll write up a text doc about building, trimming, and troubleshooting. I also need to make an assembly drawing and parts list. Oh yeah, I'll be building a simple little modular soon for actual music-playing tests. I'll want to check out the sound since I'm predicting that the ADSR's will be real snappy (see my previous DIY posts). Here's a list of the critical parts: (5) CA3140 (4) CA3080 (19) Dual op-amp, TL082, LM358, etc. (2) CD4002 (2) CD4053 (2) 2N4856 N-channel JFET (6) 2N3904 NPN (2) 2N3906 PNP (13) 100K 10-turn trimpot (2) 10K 10-turn trimpot (1) 100 ohm 10-turn trimpot A bunch of resistors and capacitors (yet to be tallied up) Optionally: (2) 1K or 2K +3300ppm/C' tempco resistors (2) MAT-02 matched NPN pair (or equivalent) Looks like there's about 2 dozen good requests so far, and I was pretty good at my first guess of $60 per board. I know that some of you out there will think that's a little pricey if you call around to the local PCB shops, but keep in mind that I'm trying to recoup my fabrication costs which will be over a grand when all is said and done. Okay, let me think out loud here, uh, I'll make the first price break at quantity (4) in the same order to $50 per PCB. This'll get you started on a cool Oberheim 4-voice clone for 200 bucks for example. Don't order yet, I'll have to make the purchase first. I'll post when I do. Also I'll have to figure out how to do this - how about I get a couple "beta-testers" who are willing to part with the money and trust me to ship out the PCB's? Then they can relate their experience to the list and tell everyone I'm a good guy. Suggestions???? - Gene gstopp@fibermux.com >From owner-synth-diy Wed Apr 24 10:14:15 1996 Date: Wed, 24 Apr 1996 13:13:55 +0300 (EET DST) From: Joachim Verghese To: Synth DIY Subject: Re: Circuit Board Update 4/23 In-Reply-To: <9603238302.AA830279598@ccrelay.fibermux.com> On Tue, 23 Apr 1996 gstopp@fibermux.com wrote: > The exponential > converter uses a pair of NPN's, so that means that a couple of > hand-matched 2N3904's should work fine. That's what I'm using right > now, and they're not even matched. What does Electronotes say about this matter? According to my experience, the two transistors of an exponential voltage-to-current converter need not be matched in the normal sense, i.e. for equal Vbe and/or Beta. The first transistor is used to provide an offset voltage for the exponentiating (second) transistor. This offset voltage contains the temperature dependent factor of the transistor's reverse collector cut-off current. If this factor is equal for the two transistors, and they're always at equal temperature, the effect will be completely cancelled. (Note that this does not eliminate the temperature dependence of the exponential scale factor (0.33%/K) which is why you still need a tempco resistor or similar). In other words, the two transistors should ideally be matched for similar temperature characteristics, and have good thermal coupling. This is perhaps easiest to achieve by using integrated transistor pairs or arrays. If you use discrete devices, I'd imagine you'd get good results as long as you provide adequate thermal coupling. (ARP used to put brass clips around their TO-92 pairs). It might also help if the two transistors are off the same manufacturing lot. Any differences in Vbe or Beta will be corrected for by the frequency offset trimmer of the VCO. -joachim >From owner-synth-diy Wed Apr 24 15:41:47 1996 Date: Wed, 24 Apr 96 08:40:26 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re[2]: Circuit Board Update 4/23 Hi Kevin, Only the bare-board PCB's, etched, drilled, plated thru holes, silkscreened, and soldermasked. It would be difficult for me to offer either kits or tested boards because I'd have to get all the parts first. I'd rather offer just the PCB's and let people come up with their own resources. - Gene ________________________ Reply Separator ____________________________ Subject: Re: Circuit Board Update 4/23 Author: K.Dunnicliffe@uk22p.bull.co.uk at ccrelayout Date: 4/24/96 11:33 AM This may be stupid of me, but can you clarify what the "deal" would be. Are you proposing to sell bare-board PCBs (etched, drilled, but unpopulated) Or to sell complete kits of PCB plus all required components unbuilt? Or to sell a built, tested, calibrated voice board for $60 ? I don't really have a feel for the costs of developing and producing these things in volume, but it seems to me you've done synth-diy a great service in the designing, laying out and debugging of a modular voice board. Count me in as interested. >From owner-synth-diy Wed Apr 24 16:14:36 1996 Date: Wed, 24 Apr 96 09:13:27 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re[2]: Circuit Board Update 4/23 (fwd) This is a really good question - although the Electronotes VCO that I'm using has linear FM inputs, I don't have any linear CV equipment at all so I can't try it to see if it will work. The linear FM inputs on the VCO go into the summing node of the reference op-amp in the exponential converter. Does anyone know if this is the proper type of linear FM for V/Hz operation? I never got into the difference between CFD and CMI linear FM. Also, what is the scale factor in a linear synthesizer? Is is 1V/1000 Hz, or some number like that? Is a PAIA the same as an MS-20? Once a scale factor is established, how do you set the initial frequency? Can two linear VCO's be made to track a musical interval, other than unison? Hey maybe John Simonton can answer this.... - Gene gstopp@fibermux.com ________________________ Reply Separator ___________________________ Subject: Re: Circuit Board Update 4/23 (fwd) Author: Steve Holloway at ccrelayout Date: 4/24/96 5:24 AM I would also be interested in the PCB that Gene has designed. One point though, do the VCO's have both V/Hz and V/Octave CV's ? - just thinking it might be nice to use the linear CV that I have on my Fatman. -Steve >From owner-synth-diy Wed Apr 24 16:35:43 1996 Date: Wed, 24 Apr 96 09:34:39 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re[2]: Circuit Board Update 4/23 Buried somewhere in Electronotes I think there is an explanation of these things, but I can't remember where. One statement I did find is that the matched-pair packages like the MAT-02 are "optimized by the manufacturer for optimum log conformance". This would be in addition to the fact that all parameters are deliberately matched and thermal equivalence is guaranteed. On my circuit board I placed the two transistors next to each other, and the tempco resistor location is next to the transistor pair. This way if the builder does use two NPN's and a tempco, he can touch them all together and hold them in place with a tie-wrap and some heatsink goop or whatever method is easiest. I've found that the +3300ppm/C' term that is left over after all other effects are compensated for does not really cause a lot of problems in a studio environment. I suppose it would be a good thing to cancel out for live use, if you were for example on stage at an outdoor festival and needed to reach up and play a beat-free lead line on your synthesizer without having to stop and tune it.... Joachim, perhaps you know of a good procedure for matching transistors for a VCO application (beyond selecting from the same manufacturing lot). That would be a good reference for the DIY list. - Gene gstopp@fibermux.com >From owner-synth-diy Wed Apr 24 23:47:26 1996 Date: Wed, 24 Apr 96 16:44:38 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: ASM-1 Circuit Board Parts List Hi DIY list, Here's the parts list for the ASM-1 circuit board: Active components: (5) CA3140 (4) CA3080 (19) Dual op-amp, TL082, LM358, etc. (2) LM311 Comparators (2) CD4002 (2) CD4053 (2) 2N4856 N-channel JFET (6) 2N3904 NPN transistor (2) 2N3906 PNP transistor Trimpots: (13) 100K 10-turn trimpot (2) 10K 10-turn trimpot (1) 100 ohm 10-turn trimpot Passive components: (6) 1N4148 Diodes or equivalent (4) 22 ohm resistor (6) 220 ohm resistor (1) 390 ohm resistor (2) 470 ohm resistor (2) 680 ohm resistor (10) 1K ohm resistor (2) 1.5K ohm resistor (3) 2K ohm resistor (2) 3K ohm resistor (2) 3.3K ohm resistor (7) 10K ohm resistor (4) 15K ohm resistor (2) 18K ohm resistor (1) 27K ohm resistor (1) 33K ohm resistor (5) 47K ohm resistor (2) 56K ohm resistor (51) 100K ohm resistor (at least 2 1%) (1) 150K ohm resistor (2) 200K ohm resistor (1) 270K ohm resistor (1) 330K ohm resistor (6) 560K ohm resistor (7) 1M ohm resistor (4) 1,5M ohm resistor (2) 2M ohm resistor (2) 18pf capacitor (2) 30pf capacitor (4) 100pf capacitor (2) 330pf capacitor (1) 0.001uf capacitor (2) 0.0022uf capacitor (3) 0.01uf capacitor (24) 0.1uf capacitor (2) 1uf capacitor, unpolarized (2) 4.7uf capacitor, 16V (2) 10uf capacitor, 16V (2) 100uf capacitor, 16V Optionally: (2) 1K or 2K +3300ppm/C' tempco resistors (2) MAT-02 matched NPN pair (or equivalent) Notes: * If you use the MAT-02 matched NPN pairs you won't need four of the 2N3904's. * You should use all metal film resistors. * The caps over 1uf are tantalums, except for the 100uf's which are electrolytic. * The 100uf caps can be any value, really, since they are just power conditioning caps on the +/- 15 volt inputs. They do need to be at least 16V however, and not too big to fit on the PCB. * The 1uf unpolarized cap can be made from two 0.47uf non-polarized caps in parallel. * There are many places where the resistor values may be changed by the builder, such as the input structures or places where the ratio of two resistors sets a parameter level. These will be discussed in the documentation that I haven't written yet. This parts list might have a couple errors in it - it is only intended to give a preliminary idea to those who might want to build one. Looks like the order for the circuit boards will be submitted this week or early next week. The PCB house turn-around time is quoted at 4 weeks, which means really only a week or two. The prototype works great on the 'scope, musical tests soon. - Gene gstopp@fibermux.com >From owner-synth-diy Thu Apr 25 16:18:22 1996 Date: Thu, 25 Apr 96 09:17:17 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re: ASM-1 Parts; MIDI->CV Yeah I admit it the parts list is for the circuit board only. Since the panel is a matter of the personal preference of the builder, I left that open. You can try to use psychic energy if you think it will work :) *But* I did write up a "suggested panel connections" page for each module, which shows a very generic modular setup. I suppose I should post a list of all the suggested panel parts, since this will be a major fraction of the cost of the final system (depending on the resources of the builder). I would consider the absolute minimum number of panel pots to be: VCO 1 Fine Tune VCO 1 Coarse Tune VCO 1 Initial Pulse Width VCO 2 Fine Tune VCO 2 Coarse Tune VCO 2 Initial Pulse Width VCF Cutoff Frequency VCF Resonance ADSR 1 Attack ADSR 1 Decay ADSR 1 Sustain ADSR 1 Release ADSR 2 Attack ADSR 2 Decay ADSR 2 Sustain ADSR 2 Release VCA 1 Initial Gain VCA 2 Initial Gain LFO Rate Glide (Portamento) Amount The Coarse Tune pots on the VCO could be octave rotary switches if desired. You may even be able to get rid of the Fine Tune pots if you use 10-turn or 20-turn panel pots for the Coarse Tune. As for any additional controls - there's two primary approaches to modulation routing in modular synthesizers - I'll call them the "Moog approach" and the "Emu approach". The Moog approach is to put all the minimum pots on each module, and dealing with modulation depths and signal strengths (really the same thing in a true modular) by the use of attenuators and mixers on seperate panels. The Emu approach is to provide all of the minimum pots on each module, and then provide additional pots on each module as input level controls for the audio as well as the CV inputs. The modules become more complex and costly, but more self-contained. Whatever you want to do. feel free. The Emu approach will probably cost more and take up more panel space, and lots of pots will go un-used most of the time, but it sure is easy to make patches. Regarding the CV and Gate inputs - the VCO and VCF CV inputs are exponential at 1 volt per octave. The Gate input is a positive V-trigger, with the threshold adjustable on a trimpot on each ADSR to be anywhere between ground and +15 volts. There is no pulse trigger input - the ADSR's require only a Gate input (positive voltage as long as a key is held down). As for MIDI to CV converters - the builder has to provide this. I personally intend to use CV keyboards, or finish up that PC-based MIDI-CV thing I started (i.e. put it in a box) or maybe even use an MPU-101 (what a great little box *that* is!). I have no experience with the PAIA or Kenton stuff, so maybe others can advise as well. - Gene gstopp@fibermux.com _________________________ Reply Separator ____________________________ Subject: ASM-1 Parts; MIDI->CV Author: Bob.Schrum@harpercollins.com at ccrelayout Date: 4/25/96 6:57 AM The ASM-1 sounds like a great and reasonably affordable project. One thing intrigues me, though... Since the parts list contains only trimpots (no panel-mount pots,) I can only guess that the ASM-1 features a "brain-wave programming interface!" :-) How did you accomplish this with such a low parts count? I see a Nobel Prize for biometaphysics in your future! ROFL Seriously, you can count me in. What kind of CV and trigger is required? Can you recommend a MIDI to CV/Trigger interface to use? >From owner-synth-diy Mon Jul 1 18:18:05 1996 Date: Mon, 01 Jul 96 11:16:25 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re: Simple Power Supply Stuff I'd say off the top of my head that the power resistors are the reason that your power supply is giving off so much thermal activity. The power supply design that I use all over the place with great success consists of the following: * 36 VCT 3A transformer, center tap to ground * Diode bridge to create +/- DC voltage * Two fairly big electrolytic caps (2200 uF 50V for example) * 7815 regulator for +15V * 7915 regulator for -15V * Misc stabilizing caps per databook That's it. No trimmers, but the outputs are usually pretty close to 15V. - Gene gstopp@fibermux.com ________________________ Reply Separator ___________________________ Subject: Simple Power Supply Stuff Author: Bob Zimmer at ccrelayout Date: 6/28/96 1:39 PM I'm building a simple power supply for the ASM-1 and am wondering about a couple of things. First a little background. The PS uses a transformer from Electronics Goldmine which has three secondaries: 28 VCT @ 2A, 18 VCT @ 1A, and 16 VCT @ 2A. I'm running the 28VCT into a bridge and into a LM317 and LM337 trimmed to +-15VDC. Yes, it does have the necessary caps and resistors. I know that the ASM-1 doesn't need +5V, but I have the 16VCT winding running into a LM7805 (just using the center tap and one of the other wires for an actual 8V). I have small heatsinks (5W or so) on the three regulators. I'm using a pair of 10 ohm 10W power resistors in series to load the +15 supply and another pair for the -15V supply to .75A each. My DMM reads about .73A so I know this is close. The questions are: 1. When running like this, each supply is dropping about 4.3 Volts (1.3V over the minimum) at .75A. After a few minutes, the heatsinks seem to get too hot to touch, but the regulators do not shut down! How can I tell if this is too much heat for normal operation? 2. The power resistors also get very hot and actually put off an odor from the heat. Is this normal? As far as my math allows, everything should be within tolerances for current and wattage. >=== Bob Zimmer -- Philadelphia PA ===< >=== bzimmer@voicenet.com ===< >From owner-synth-diy Tue Jul 2 20:10:44 1996 Date: Tue, 2 Jul 1996 16:10:26 -0400 To: synth-diy@horus.sara.nl From: Bob Zimmer Subject: RE: Simple Power Supply Stuff Wow!! Thanks for all of the replies!! With all the questions asked, maybe I should have added more info to the original post? This is the first "anything" that I've tried to design from scratch. I thought that I'd start with something simple. I started by setting out some basic design goals: 1) Power supply must fit into a 3.5" rack chassis along with my ASM-1. 2) The entire Power Supply should fit onto a 3x5" pc board. 3) It must provide +15V and -15V at 1/2A per supply. 4) It must power both the ASM-1 and a second analog circuit board with minimally: an additional LFO, Sample & Hold, Ring Modulator and possibly one or two waveshapers. 5) The design would use a 28 VCT transformer that I already have. It will mount easily on the 3x5" board with room for the remaining components. 6) It will use LM317/337's as they provide 80 dB of ripple rejection with two small caps added to the basic circuit Vs. 65 dB for the LM7815/7915. This would allow me to reduce the size of the main filter caps to 1000 uf or 1500 uf and still have the same quality on the output. Did I spend too much time in National Semiconductor's Databook??? Design as tested: The supply for +-15V uses the 28VCT 2A secondary by using the center tap as the ground line and the other two wires connected to a 100V 2A Bridge Rectifier. The positive output of the rectifier runs to the LM317 (+ Reg) and the negative output runs to the LM337 (- Reg). The main filter caps are 1500 uF 35V. There is also a 1 uf Tantalum across each regulator output and a 10 uf 25V cap in the adjustment line to get the 80 dB regulation. Other than that, there are two resistors per supply and one 15T trimmer. There is a 240 ohm resistor between the output of the regulator and the adjust line. There is a 2.2K in series with a 1K trimmer between the adjust line and ground to trim the output voltage to 15V. I don't have the ASM-1 finished yet to load the Supply, so I simply put a pair of 10 ohm power resistors (connected together in series to create a 20 ohm load) across the output connections of each regulator (+15 and -15). The 10 ohm was the best choice that I could find quickly (from Radio Shack). My math says: I = E / R I = 15V / 20 ohms I = .75A This turned out well as I measured a true load of .73A or so on each supply. The input voltage to each regulator at this load measures 19.3VDC which should be just enough above the necessary 18VDC. I also figured that: P = E * I P = 15V * .75A P = 11.25 Watts I counted on each resistor dropping half of the voltage, therefore 10W should have been sufficient. I think that a real load will vary in current draw over time (depending on levels, waveforms, etc.), but felt that the Power Resistors would be a fair "smoke test" and allow me to check the heat sinks to see if they were sufficient in size. My question on Duane's comments: Whoops! I was under the assumption that if I had put in a pair of resistors across the output, then each would be dropping about half of the voltage & current. The 11.25W is definitely too much for one 10W resistor, but with the pair, I was expecting that each resistor would be dropping 5.6 Watts, which should be within their 10W rating. Why isn't this true?? I can't find an explanation in my electronics books. My comments on Barry's Klein's comments: On the transformer voltages, agreed, but if I keep the total output of each supply to about 1/2A, shouldn't the 28VCT should work for this application? At the .75A load, I'm measuring 19.3VDC input to the LM317T regulator which should be be fine to deliver 15V (15V output + the 3V needed by the LM317). It's not that I was trying to get the regulators to shutdown from heat. I was simply trying to run the Supply to verify that the heat sinks were sufficient by checking their temperature as they heated up. I turned the supply off once I couldn't touch them any longer. My comments on R. G. Keen's Post: Thanks much for the description of working temperatures!! It is an area that confuses the heck out of me!! Yes, my goal is to put it in a box with little airflow. How did you know? ;-) It seems from all the responses that my little heatsinks will have to grow and maybe even get mounted on the rear panel. My comments on Mark (MACHINE MEDIA)'s Post: What I think I found out is that the transformer is expected to deliver 28V RMS at the rated 2 Amp output. If the load is less (I only plan on it delivering 1A), then the voltage is somewhat higher. Such as it may start at 40V with no load, and drop from there as the delivered current rises. I am trying to allow for 18V to be available to the regulator at the desired 1/2A output current. I will watch the input AC line voltage! Never thought about checking it. My comments on Scott Gavenhorst's Post: Completely agree on "Too hot to touch is too hot"! I need to make it Run cooler since I want to enclose it. What I'm wondering is just how hot these regulators need to run and how big a heatsink is needed to get their temperature down. I wasn't getting any smoke out of the resistors, but I did shut the supply down after having it under load for about 4 or 5 minutes. I found a book at Radio Shack on building power supplies that seems to be very good for the $4.95 price, but it just skims the surface on a lot of these calculations, especially on the math and temperature calculations. My comments Gene (ASM-1) Stopp's Post: I think that Gene is saying that by using Power Resistors as a dummy load, I'm not simulating real conditions, therefore the regulators are working harder than necessary??? I have been unable to find any 36VCT 3A transformers on the surplus market. All that I've found are new ones going for $30+ each. Does anyone know of a source for a reasonable one? Thanks again to all and sorry for the long post! Bob >=== Bob Zimmer -- Philadelphia PA ===< >=== bzimmer@voicenet.com ===< >From owner-synth-diy Mon Jul 22 22:05:30 1996 From: Troy Sheets Subject: ASM-1 building update... To: synth-diy@horus.sara.nl Date: Mon, 22 Jul 1996 15:05:25 -0700 (PDT) I just received all the board components from Mouser Electronics for the ASM-1. Mouser had everything except for Tempco resistors. I didn't see if they had the MAT-02 matched transistor pair. The grand total for the board components including resistors, ICs, opamps, caps, trimmers, ect. and a +-15Volt regulated power supply was US$140.00 This did not include pots, a panel enclosure, banana jacks, or misc. hardware. Mousers number is 800-346-6873. To make things easier, here is my Mouser parts list. Notice that I have ordered some extra compnents, just in case: Power Supply: 597-AD15-0.4 +-15V 1 ICs: 570-CA3080E 5 570-CA3140AE 6 570-CD4002BE 3 570-CD4053BE 3 511-LM311N 3 511-LM358AN 3 511-TL082CN 19 333-2n4391 3 333-2n3904 3 333-2n3906 3 1% Tolerance Metal Film Resistors: part value quantity 271-22 22 5 271-220 229 7 271-390 390 2 271-470 470 3 271-680 680 3 271-1K 1K 12 271-1.5K 1.5K 3 271-2K 2K 4 271-2.2K 2.2K 2 271-3K 3K 3 271-3.3K 3.3K 3 271-10K 10K 10 271-15K 15K 5 271-18K 18K 3 271-20K 20K 4 271-27K 27K 2 271-33K 33K 2 271-47K 47K 6 271-56K 56K 3 271-100K 100K 55 271-150K 150K 2 271-200K 200K 3 271-270K 270K 2 271-330K 330K 2 271-390K 390K 3 271-560K 560K 10 271-1M 1M 9 271-1.5M 1.5M 5 271-2M 2M 3 Multilayer Ceramic Capacitors: 140-cd50s2-018J 18pF 3 140-cd50s2-030J 30pF 3 140-cd50s5-101J 100pF 5 140-cd50s5-331J 330pF 3 Ceramic Caps: 581-uec102J1 1000pF 2 581-uec222J1 2200pF 3 581-uec103J2 .01uF 4 581-udz104K1 .1uF 27 581-udz105K2 1.0uF 3 Tantalum Caps: 581-4.7k25v 4.7uF 3 581-10k25v 10uF 3 Electrolytic Caps: 539-tkr25v100 100uf 3 enjoy, -troy ------------------------------------------------------------------ tsheets@cyborganic.net <- You have found me tsheets@schwa.sun.com <- Official Use Only http://www.cyborganic.com/People/tsheets <- Instant Content troys-list@schwa.sun.com <- Inquire Within >From owner-synth-diy Tue Jul 23 16:17:26 1996 Date: Tue, 23 Jul 96 09:17:20 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re: ASM-1 boards received 2 Gee guys thanks for the compliments - About the VCA inputs: The (-) input on the VCA is just an extra input that happens to invert the signal as it goes through the VCA. The VCA's on most synthesizers have this capability but it's just not always brought out to a panel jack. The Moog 902 for example has two input jacks, and the upper one is (+) and the lower one is (-), and it's not even labelled on the panel! In practice for audio signals there is not much difference between the two (as long as you watch out for cancellation effects with signals that originate from the same sources within a modular system). For low frequency moduation applications, the (-) input can be used to invert the signal whose amplitude is being controlled by the VCA - therefore you can use the VCA as a voltage-controlled inverter. Hey - I've been meaning to ask this for some time - has anybody got an ASM-1 completely up and running? I had one running on the workbench in the garage for a while, just hooked up in a test configuration, but I had to take that apart when my wife and I bought a new house. Since we're still unpacking, I still haven't had the chance to put together a fully modular patchcord system yet. Any feedback? Any problems finding parts, or assembling, or adjusting? I know I put a disclaimer on my documentation that pretty much said "here you go, figure it out", but I may have worded it a little too strong because I haven't really seen any operational questions yet. If anybody has one up and running yet, maybe you can relate your experiences to the list. BTW there's only 5 PCB's left. I anybody's planning on making a quantity buy, let me know and I'll have another run of boards made. - Gene gstopp@fibermux.com __________________________ Reply Separator _____________________________ Subject: ASM-1 boards received 2 Author: niklasl@eritel.se (Niklas Lindberg) at ccrelayout Date: 7/23/96 3:33 AM Hi list, Would like to second Kevin Dunniclife (and others) on the excellency of Gene Stopp's ASM-1 boards (and the included documentation)... Gene has certainly produced a first class DIY-project here! I received my 2 boards on my vacation a week ago and has already bought parts for the PCBs (not panel pots, PS and HW). It came down to a measly 270$... :-\ Well, not to bad considering this is Sweden and the fact that I bought larger amounts than needed of almost all components. (and I used MAT-02s, expensive!) Building soon to commence ! BTW, There was a question on the list a while ago regarding how the - input featured in the ASM-1 VCA circuit should be used... Was this question ever answered ? (did I miss it?) If so, could someone (Gene ?) please repeat for me ? And once again: Thanks Gene! >From owner-synth-diy Wed Jul 24 15:59:48 1996 Date: Wed, 24 Jul 96 09:01:01 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re: ASM-1 2N4391 Primitive ASCII pin diagram for 2N4391/2N4392 JFET: TO-18 Metal Can Package D --- / \ S | o | G | o o | tab ---> /\ / \/ --- **** Bottom view - pins pointed towards your eyeballs **** S = source D = drain G = gate In the ASM-1 VCO: Source = goes towards CA3140 (-) input Drain = goes towards CA3140 output Gate = comes from LM311 output - Gene ________________________ Reply Separator __________________________ Subject: ASM-1 2N4391 Author: yrrab@well.com (Barry Bernard) at ccrelayout Date: 7/23/96 11:39 AM Hi people of the list, I bought some 2N 4391 jfets from Mouser for the ASM 1 board, but I'm not sure what the pinouts are on these guys. I'm guessing that the lead closest to the little tab that sticks out on the can is the source, the middle lead is the drain and the far one the gate. Anyone know for sure ? -Barry >From owner-synth-diy Fri Jul 26 22:02:30 1996 To: synth-diy From: Christopher List Date: 26 Jul 96 17:49:32 Subject: ASM-1 Faceplates for sale (?) Hi List - I talked to Gene a while ago about this, then dropped it because I thought it would be too hard to get something everyone was happy with... Since then I've gotten my girlfriend into synths, so I've been thinking about giving her an ASM-1 with a small analog sequencer built into a briefcase as a birthday gift. This has prompted me to pick up the following idea again.... My idea was to get faceplates made for the ASM-1 in the same way that Gene made the PC boards, then sell them to cover the set-up costs. It's been a while since I looked into it, but I know there are some places nearby where I can get faceplates done with high quality silkscreens for about $40-60 each. The layout I'm working on is as follows: - 4-space standard rack size - White lettering on black aluminum - Holes are spaced to accomodate up to 1/4" jacks (obviously this leaves enough room for banana jacks) holes for jacks are marked by a small "+" that's smaller than an 1/8 jack - so it won't show. - It's up to you to drill all holes (the place I was gonna take this to will drill holes, but then they may be the wrong size for some people) - Dial markings are for knobs with a max "skirt" diameter of about .85" - Pots of up to 1" diameter will fit behind the panel, knobs are spaced at least 1.3" center to center - Border of .8" on each side for standard rack rails - Border of at least .4" on top and bottom - Dial markings are very Serge-like - I figure we could mount the ASM-1 board behind the front panel, parallel to the panel, using 1" stand-offs (the board is smaller than 17"x6") I've included some changes / additions to Gene's design based on my own tastes (sorry Gene!) it's stuff like this that I struggled with when deciding to do this, I've outlined them below. I've included the following knobs / jacks ** VCOs (2) Jacks: 2 * 1v/oct Synch In FM in PWM In Knobs: Course Tune Fine Tune FM amount PWM Amount ** VCF Jacks: 3 * 1v/oct 2 * Audio In Audio Out Knobs: Frequency (I never use fine tune for filters) Q LowPass / Highpass x-fade Switch: Bandpass or Lowpass/Highpass I had one of these same filters that I built before the ASM1 came out with the four separate outputs. Then the discussion came up about the SEMs and how they can x-fade between the LP and HP (with notch in the middle). This sounded cool, so I tried it and use it all the time - I'd never go back to four separate outs. This will require a few minor modifiations to the circuit, but no extra parts (except for the x-fade pot!) I will include detailed instructions with the faceplate. I'd also like to add a knob for volume for one of the audio inputs, but I don't know if I can fit it... ** ADSRs (2) Jacks: Gate Output Knobs: Attack Decay Sustain Release ** VCAs(2) Jacks: + In - In CV In Out Knobs: Initial level ** LFO Jacks: Triangle out Square Out Knobs: Rate ** Glide Jacks: In Out Knobs: Rate ** Noise Jacks: White Pink LF The following are things that will be on the faceplate and are NOT part of the ASM circuit board. The circuits, however, are TINY (I'm talking 2 8-pin IC's and about 8 resistors), they run off of the same power supply, and can fit onto a little protoboard or something... (or you could just sand the markings off of the faceplate!). Again I will include detailed instructions for building these extras (I'd even send an AD633 for the ring mod if our European friends can't find them). ** Ring Modulator Jacks: In 1 In 2 Out ** Inverting CV Scaler - Scales CV from -cv to +cv or can be used with audio Jacks: In Out Knobs: Scale I'm not quite done with the layout, but it's close. The really nice thing is that I can send .gifs to anyone that interested, so they can see waht it'll look like before hand. What do you guys think, is it worth it? Anybody interested? I will be away for the weekend, so I'll reply on Monday. - CList >From owner-synth-diy Fri Jul 26 23:28:07 1996 From: Dan Higdon To: synth-diy Subject: RE: ASM-1 Faceplates for sale (?) Date: Fri, 26 Jul 1996 18:24:41 -0500 Great idea! I have a faceplate design I've worked out based on some ideas from Ric Miller. Because I've managed to shrink it WAY down (4k JPG), I can easily post it to the list, if anyone's interested. Basically, it's a 6 space panel, with each "module" in a single space All knobs are left aligned, all jacks (banana) are right aligned. It's not too crowded, and very "regular". The spaces are: VCO1 VCO2 VCF Dual ADSR Dual VCA Misc (LFO, SLEW, NOISE) It's really much easier to just send the JPEG, so if anyone is interested, I'll post it. (I have a larger, more legible version as well, btw) If we get enough interest, we can probably get some made. I will most likely get 2 made anyway, unless Christopher's panel appeals to me more. :-) Later, Dan Higdon (hdan@charybdis.com) >From owner-synth-diy Sun Jul 28 00:14:08 1996 Date: Sat, 27 Jul 1996 20:13:04 -0400 To: synth-diy@horus.sara.nl From: mathias@cstone.net (Mathias Tornqvist) Subject: Re: ASM-1 Faceplates for sale ALthough I, like Jupiter4, haven't had the cash to buy one of Gene's boards, I have very firm plans to do so whenever I get the chance (so go ahead and make another batch, Gene!) My plans for the layout are very similar to Christopher Lists, but a few small changes on his design would make it perfect (for me...) >** VCOs (2) >Jacks: >2 * 1v/oct >Synch In >FM in >PWM In > >Knobs: >Course Tune >Fine Tune >FM amount >PWM Amount How about sacrificing the sync input on one VCO and have a linear FM input instead (is linear FM availible in the ASM-1?) >** VCF >Jacks: >3 * 1v/oct >2 * Audio In >Audio Out > >Knobs: >Frequency (I never use fine tune for filters) >Q >LowPass / Highpass x-fade > >Switch: >Bandpass or Lowpass/Highpass I'm not sure what I'd use 3 1v/oct inputs for on a filter. It seems more flexible to have 2 inputs, and an Amount knob for one of them. If the Bandpass is integrated with the X-fade pot (SEM style), you'd have room for a Balance knob between the two audio inputs. ... >** VCAs(2) >Jacks: >+ In >- In >CV In >Out > >Knobs: >Initial level How about a Modulation Amount knob? then you can adjust AM amount from VCO's, direct-patch the LFO without getting a mega-tremolo. Envelope to VCA could be adjusted for level control (Odyssey-style) Other than these, the layout is similar to what I had in mind. I'd use banana jacks, since there aren't any mults planned. Question: Would it be possible to stack banana plugs to inputs of the synth without getting inpedance/level matching problems? For example, run two VCO's into a VCA input without any mixing circuitry? I also had another thought... A matrix patchable version (EMS-style) would be compact, tidy and cute. But since pin-matrixes are hard to get to these days, how about a grid of dip switches? For example 16 12-position dips stacked vertically, the 12 position representing outputs, and the 16 rows representing inputs. Are there 16-poition dip switches? 12 outputs may be a bit restricted. Perhaps 8+8x16... Would this be too flimsy, fragile and generally unbearable? It wouldn't be too expensive (16x$2 for 12 position switches), and pretty compact (6.5"x1.3") Any thoughts? Alternatives? Mathias Tornqvist >From owner-synth-diy Mon Jul 29 14:50:41 1996 From: Dan Higdon To: "'Synth-DIY'" Subject: ASM-1 Faceplates by hdan Date: Mon, 29 Jul 1996 09:47:59 -0500 Ok, I've had enough requests that I feel justified in breaking nettiquette (sp?) by posting my JPEG. It's only 4k, so it shouldn't hack off too many people (I hope!). This is the "small" version. You can still make out most of the labels. My philosophy is this: Since I'm building extra modules for myself, I want the ASM panel to be made in such a way that it will visually and operationally integrate with my other modules easily. To that end, I've adopted a stadardized single-space layout of up to 8 knobs, followed by up to 12 jacks in double rows. (I'm intending to use banana plugs everywhere). I also have decided to always include 2 modulation jacks with independent level controls for each "parameter". You'll also notice that I've included 2 "straight CV" connections for the "tuned" modules (VCO, VCF). One might be enough, but I had the space on the panel, and the inputs on the ASM-1 board. For jack, my philosophy was to left justify inputs and right justify outputs within the "jack area". This seems pretty workable. If anyone has a better idea about placement of jacks/knobs (such as which position or order) within this scheme, let me know. Also, if the order in which modules appear on the panel isn't good, let me know as well. That last module is just "all the stuff that didn't fit above", so I'm totally open to better ideas there. Enough blabbing, here it is. 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synth-diy@horus.sara.nl Subject: Re: ASM modules and the electronically challenged Assuming the documentation for an electronic kit is correct, there are really two requirements to guarantee that a kit will work correctly: 1. Use the proper and appropriate components 2. Assemble the components without damaging them and without creating electronic shorts or opens For the ASM-1 kit, the first requirement is very important because I sell only the circuit board and none of the components. In my documentation I do specify what components can be swapped out for others as much as possible. I believe that there is definitely an aquired artistry to knowing and buying the right components, that takes a while to nurture, and a kit like this is exactly the kind of learning tool to help this process out! As for the second requirement, you just need some good soldering skills and awareness about ESD damage. Normally ESD isn't much of a problem with analog circuitry but the ASM-1 does use the CA3140, which is a CMOS input op-amp, and quite easily blown up. It may be that, as the designer, it's hard for me to assemble one of these as if it was my first project, but I did manage to assemble one just by going by my assembly drawing, and it worked fine on first power-up. So I think that I can safely say that if the right components are soldered in the right places with good technique, the board will function 100%. Boards are available, and looks like I'll send out for another batch of 50. - Gene gstopp@fibermux.com p.s. yes it's $60 USD. ______________________________ Reply Separator _________________________________ Subject: ASM modules and the electronically challenged Author: keithw@cix.compulink.co.uk at ccrelayout Date: 7/28/96 9:30 PM Hi list, I have only recently joined the list and am delighted to find so much going on, I have been into synths since hearing 'popcorn' as a child and seeing the large bloke on the back of the 'Hot Butter' album tweaking the moog! (sad but true). I am very interested in the ASM board from Gene, and also in the face plates and mods from Christopher, (I would like to hear more about the small analog sequencer as well). The problem I have is I am not very experienced in electronics, sure I can get the odd faulty synth going again if it is just a case of replacing a chip or so, (I have a lovely Roland SH2 as proof of that). I am very good at soldering but how much technical knowledge and equipment do I need to build an ASM module? I could assemble the board easily enough, I have a soldering iron, a simple multimeter and know one end of a component from the other, but I am not sure about setting it up and getting the power supply right. I don't know how complicated the kit is and how much setting up is required. Is it just a case of assembling the board and wireing up the knobs and sockets? I would like some feedback. I might be able to get one of my friends over here to help me set it up (loads of experience of big analog modulars), but would like to attempt it myself an not hassle him! Any comments welcome -be kind! I hope to be ordering a board soon, I hope there are some left Gene. I am just figuring out the best way to get $60 to you from Manchester UK. (is that price correct?) >From owner-synth-diy Mon Jul 29 17:09:25 1996 Date: Mon, 29 Jul 96 10:11:53 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re[2]: ASM-1 Faceplates for sale A couple quick points... Yes the ASM-1 does have linear FM inputs on the VCO's. My inclination is to always have at least one variable attenuation input per summing node on every module. The ASM has some pretty wide sweep ranges so mod depth pots would be highly recommended. You may be able to get by with only a course tune control on the VCO's if you use a multi-turn pot, but these things are quite expensive and should be tried before committing them to a panel. As for banana plug stacking on inputs - be sure that all outputs have 1K resistors (i.e. add them to the outputs that come straight off of the op-amps). Then you can stack away, input or output. However be aware that stacking two outputs together means that you will have two signals fighting each other at 1K impedances, on a 100K input, so that the actual composite signal will be averaged rather than summed. Therefore two five volt waveforms will peak at five volts when mixed as an average, but will peak at ten volts when mixed as a sum (2 seperate inputs). - Gene gstopp@fibermux.com ____________________________ Reply Separator ______________________________ Subject: Re: ASM-1 Faceplates for sale Author: mathias@cstone.net (Mathias Tornqvist) at ccrelayout Date: 7/27/96 5:33 PM How about a Modulation Amount knob? then you can adjust AM amount from VCO's, direct-patch the LFO without getting a mega-tremolo. Envelope to VCA could be adjusted for level control (Odyssey-style) Other than these, the layout is similar to what I had in mind. I'd use banana jacks, since there aren't any mults planned. Question: Would it be possible to stack banana plugs to inputs of the synth without getting impedance/level matching problems? For example, run two VCO's into a VCA input without any mixing circuitry? >From owner-synth-diy Wed Aug 7 18:51:16 1996 Date: Wed, 7 Aug 1996 14:52:31 -0400 (EDT) To: synth-diy@horus.sara.nl From: Bob Zimmer Subject: Progress on ASM-1 This is some possible suggestions for those of you that are building ASM-1's! What I've found is that it is very possible to build this board section by section. If you are not experienced at building or at all unsure of your soldering ability, it can be done and works! I started with the LFO, then moved onto the Noise Source, then onto the first VCA (nearest the large power capacitors) then onto the last VCA and Glide Processor. In doing this, it allows you the chance of getting the board working section by section, and creating your signal options as you go. For example: Warning: In several places I suggest using headphones for testing. Please realize that the ASM-1 puts out a significant signal which will blast your ears! If at all possible, use phones with a volume control or run the output thru a pot. Before turning on the ASM-1, please make sure the volume control is turned all the way down!!! 1. Build and test the LFO. If you install the LED, or a bi-color (red/green) as I did, you can easily test it if you do not have a scope. Of course if you have one or can borrow one do so as it will make everything from here forward much easier. 2. Build and test the Noise Source. This can be tested by connecting a jack and headphones (or scope!). Note that the signal does not look like more than just a wide pulse on the scope. It would probably look like more on a spectrum analyzer (comments anyone?), but might be best tested with headphones? 3. Build the first VCA. This can be tested by using White or Pink noise as an audio source, and the LFO (set to a very low frequency) as a CV Source. Again, if you don't have a scope, try headphones on the output! 4. Build the second VCA. Test the same way as the first VCA. 5. From here you can move onto the Filter and ADSR's in any order. If you build an ADSR next, connect the output into the CV input of the VCA and use the noise source for an audio signal as in step 3. If you build the filter, you can use the LFO or ADSR for a CV signal and the noise source for an audio signal. I'm working on a couple of modifications for the ASM-1, namely a range switch for the LFO to get lower frequencies, the bicolor LED (looks pretty more than anything!), and switching to allow the glide processor to be used as exponential or linear. Later, I'll add an add-on board containing a sample hold, ring modulator, and some additional waveforms. When I have these done, I'll post them on my home page. I'll give the address when I'm ready and there is something to see! Bob >=== Bob Zimmer -- Philadelphia PA ===< >=== bzimmer@voicenet.com ===< >From owner-synth-diy Wed Aug 7 21:17:31 1996 Date: Wed, 07 Aug 96 14:20:01 PDT From: gstopp@fibermux.com To: synth-diy@horus.sara.nl Subject: Re: Progress on ASM-1 Here are some comments about the ASM-1... I just realized that I didn't include any notes in my documentation about actually listening to the thing - Bob's right, the signals would be way above line level and should be attenuated before amplification. It's probably a good idea to include a master volume pot on the final machine. One may be tempted to run the final VCA direct into the mixing board and pad it there, but the board's preamp will probably be overdriven. At this point one may be further tempted to cut down either the input to the VCA or its control CV, then go straight into the board, but your signal-to-noise will not be so good. Better to run the VCA input hot, and the control CV full-strength, then cut it down with a volume pot *after* the VCA output for the best S/N ratio. The noise source "Level" trimpot will adjust the noise level from zero to max - somewhere in between is a good setting. I would probably adjust it so that the pink noise output sounds about as loud as a VCO waveform. The ear is much better than a scope for noise, since to see the whole picture on the scope you'll probably need to set the vertical to 5 volts/div and the horizontal to a real slow sweep just to get a band of fuzz across the scope screen. As the LFO rate pot is turned almost all the way down (attenuating the square wave down to almost nothing to the input of the integrating op-amp), the LFO frequency will slow down towards zero hertz. Once the integrator's input is at ground, the LFO will stop and the triangle output will probably slowly drift to either the (+) or (-) supply. The minimum frequency before this happens will be determined by a couple things - first, the resolution of the rate pot near the lowest setting, and second, the leakage currents of the TL-082. If you aren't using a TL-082 here, I suggest that you do because something like an LM358 or 1458 will not go to nearly as low a frequency before "stalling". Also remember to de-flux the circuit board because solder flux residue will cause leakage currents and prevent really low frequencies. In my drawing I showed a minimum frequency resistor in series with the LFO rate pot on the ground side, but I forgot to mention the LFO in my documentation. You can experiment with this to get the lowest frequency - try around 22 ohms first. Of course you can make it zero ohms and let your LFO "stall" at the lowest setting, providing you with a source of (-) voltage or (+) voltage, depending on where it was when you turned the pot down all the way. Many times in my homebuilt stuff I got confused by something like a pulse wave that was silent or a filter that was shut down, and finally stumbling on the fact that an LFO had stalled taking the pulse width or filter cutoff with it. If you like a certain "danger factor" in your performances, then by all means let your LFO's go down to stall speed. I personally like to be fooled by the machines once in a while. If you do want to add a range switch to the LFO, probably the best way to do it is to switch in another cap across the LFO's integrator. This may be a little messy since you will need to add wires to the component on the board, or run wires from the capacitor's location on the PCB and mount your capacitors on the panel switch. Also, bi-color LEDs are always fun to have in DIY synthesizers. Have fun! - Gene gstopp@fibermux.com >From owner-synth-diy Thu Aug 8 10:39:51 1996 From: Haible_Juergen#Tel2743 To: DIY Subject: AW: Re: Progress on ASM-1 Date: Thu, 08 Aug 96 12:38:00 PDT > As the LFO rate pot is turned almost all the way down (attenuating the > square wave down to almost nothing to the input of the integrating > op-amp), the LFO frequency will slow down towards zero hertz. Once the > integrator's input is at ground, the LFO will stop and the triangle > output will probably slowly drift to either the (+) or (-) supply. The > minimum frequency before this happens will be determined by a couple > things - first, the resolution of the rate pot near the lowest > setting, and second, the leakage currents of the TL-082. If you aren't > using a TL-082 here, I suggest that you do because something like an > LM358 or 1458 will not go to nearly as low a frequency before > "stalling". Also remember to de-flux the circuit board because solder > flux residue will cause leakage currents and prevent really low > frequencies. For a 1458, leakage (input current) would indeed be the limiting factor. But not for the TL082. There is another effect, and that's the offset voltage of the opamp that forms the integrator! Assume you have -1mV offset voltage, then positive voltages below 1mV will not be able to change the integration direction anymore! You can easily check if offset voltage is the bad guy: with decreasing frequency the rectangle would become more and more unsymmetrical, until you reach the 0% or 100% point and oscillation stops. In my modular, I have added an offset compensation to the LFOs. Then I could use 10k log pots together with a very small "foot" resistor (I think it was below one ohm!), and the LFO still oscillates. (This is about general Tri/rectangle LFO's - I don't have Gene's schematics right in front of me now, so I am not sure if it applies to this) JH. >From owner-synth-diy Fri Aug 9 20:40:54 1996 From: Troy Sheets Message-Id: <199608092040.NAA11942@xanadu.cyborganic.net> Subject: Re: chassis grounding To: yrrab@well.com (Barry Bernard) Date: Fri, 9 Aug 1996 13:40:48 -0700 (PDT) Cc: synth-diy@horus.sara.nl In-Reply-To: from "Barry Bernard" at Aug 9, 96 10:49:23 am It is always a good safety precaution to ground your chassis!!! If anything "hot" touches the chassis (like AC power) and the chassis is grounded, it will more or less harmlessly flow through the ground and trip a breaker. If it is not grounded, the electricity might instead flow through you! -troy > Hi list, > > I have a question. I am building my ASM-1 project in a metal chassis. Should > the chassis be connected to ground or not ? The holes for the mounting > screws on the board are smack in the middle of the ground traces, but I > could use plastic > standoffs if this isn't a good idea. what do you think ? > > -Barry >From owner-synth-diy Fri Aug 9 22:56:45 1996 Date: Fri, 09 Aug 96 15:59:54 PDT From: gstopp@fibermux.com Message-Id: <9607098396.AA839631624@ccrelay.fibermux.com> To: synth-diy@horus.sara.nl Subject: Re: chassis grounding Within a self-contained system such as a synthesizer I always just ground everything together - the circuit board ground, the panel, the jacks, the box, and the third prong of the AC power cord. Works fine for me so far. I think that you only run into ground loop problems when interconnecting machines together whose AC power comes from different and/or distant outlets. You can lift the synthesizer housing from the third prong if you want to avoid potential ground loop problems. What I would do in that case is make sure that the power supply ground terminal (usually the center tap of the bipolar supply transformer winding) is connected to the box, jacks, and circuit board ground. - Gene gstopp@fibermux.com ____________________________ Reply Separator _______________________________ Subject: chassis grounding Author: yrrab@well.com (Barry Bernard) at ccrelayout Date: 8/9/96 11:03 AM Hi list, I have a question. I am building my ASM-1 project in a metal chassis. Should the chassis be connected to ground or not ? The holes for the mounting screws on the board are smack in the middle of the ground traces, but I could use plastic standoffs if this isn't a good idea. what do you think ? -Barry >From owner-synth-diy Wed Aug 28 09:10:55 1996 From: Haible_Juergen#Tel2743 To: DIY Subject: AW: chassis grounding Date: Wed, 28 Aug 96 11:07:00 PDT > I have a question. I am building my ASM-1 project in a metal chassis. > Should the chassis be connected to ground or not ? The holes for the > mounting screws on the board are smack in the middle of the ground traces, > but I could use plastic standoffs if this isn't a good idea. > what do you think ? My preferred method: The enclosure is grounded (for obvious safety reasons), but this enclosure ground is not identical with Signal Ground. (Insulated Jacks!) Now at one point I connect the two gronds by two strong diodes (1N4007) (is "reverse parallel" the right word?), and a 47nF ceramic in parallel to the diodes. This method is perfect for me: Ground loops see a high impedance (47nF at 50Hz), and a high (in terms of Hum) 0.7V threshold voltage. Safety is good for this very unit (earth ground on enclosure), and even other units that are connected to this one are somehow protected (the dides can carry a lot of current if they have to!). And the 47nF capacitor gives almost perfect shielding for the electronics, because in terms of electromagnetic fields it is rather low impedance, so for shielding signal ground and enclosure ground are almost identical. JH. PS.: My largest project, the JH-3 Modular, is an exception of this: I have lots of non-isolated jacks on aluminium front panels. But I won't connect this to Earth Ground at all - just take care that the PSU is perfectly insulated (epoxy, perhaps). >From owner-synth-diy Fri Oct 4 04:50:16 1996 Date: Thu, 3 Oct 1996 21:46:50 -0700 (PDT) To: synth-diy@horus.sara.nl From: yrrab@well.com (Barry Bernard) Subject: ASM-1 up and running >Okay, I got my drill... my pots... my jacks... my 7 pound steel 19x10.5 >inch panal.. my knobs... I get to start building my ASM-1 panal this >weekend! > >I will get some pictures up of it as soon as I finish it. > >-troy Just thought I'd mention, I have my ASM-1 project up and running. I built it with the maximum amount of pots and jacks. Almost everything worked perfectly right off the bat. It sounds great ! I'm still ironing out a few problems here and there. One thing I recommend is soldering in the "optional" 30pf capacitor across the feedback resistor of the VCA, otherwise you will get high freq oscillation on the output of the VCA's, only at a certain control voltage input level. This can be heard as "clicking" when you modulate the VCA every time you pass that certain voltage. Adding the capacitor gets rid of the problem. One thing that has me stumped is that the with really low frequencies (like less than 1 hz), the output of the LFO seems to be asymmetrical. On the triangle wave, the rising part takes a lot longer than the falling part. On the square wave, the voltage stays low for much longer than it stays high. I believe I just used a ceramic dip capacitor, could this be the problem ? Apparently it's discharging faster than it's charging at low frequencies. Also, although my LFO goes well up into the audio range, it stops oscillating when it gets below around .2 hz. Of course I'd like the LFO to do really slow sweeps. As far as I know I put the proper components in. Anyone have any suggestions ? regards, -Barry >From owner-synth-diy Fri Oct 4 07:14:56 1996 To: yrrab@well.com (Barry Bernard) cc: synth-diy@horus.sara.nl, magda@it.kth.se From: Magnus Danielson Subject: Re: ASM-1 up and running In-reply-to: Your message of "Thu, 03 Oct 1996 21:46:50 MET." Date: Fri, 04 Oct 1996 08:14:00 +0100 Barry wrote: > One thing that has me stumped is that the with really low frequencies > (like less than 1 hz), the output of the LFO seems to be asymmetrical. On > the triangle wave, the rising part takes a lot longer than the falling > part. On the square wave, the voltage stays low for much longer than it > stays high. I believe I just used a ceramic dip capacitor, could this be > the problem ? Apparently it's discharging faster than it's charging at low > frequencies. Also, although my LFO goes well up into the audio range, it > stops oscillating when it gets below around .2 hz. Of course I'd like the > LFO to do really slow sweeps. As far as I know I put the proper components > in. > Anyone have any suggestions ? Well, I try to avoid the ceramic cap's as much as possible... they leak considerable more than certain other type's in the same range. When I go about building my ASM-1's I will use plastic caps (probably polypropylene... they are quite cheap anyhow). There are polypropylenes available at 1uF (not as cheap, but you use up only one per ASM-1 board....). You can use polycarbonate or polystyrene as well... mylar (polyester) should also make an improvement... Hope it helps... Cheers, Magnus >From owner-synth-diy Fri Oct 4 13:43:58 1996 Date: Fri, 4 Oct 1996 09:42:57 -0400 (EDT) From: Tony Clark To: Barry Bernard cc: synth-diy@horus.sara.nl Subject: Re: ASM-1 up and running In-Reply-To: > One thing that has me stumped is that the with really low frequencies > (like less than 1 hz), the output of the LFO seems to be asymmetrical. On > the triangle wave, the rising part takes a lot longer than the falling > part. On the square wave, the voltage stays low for much longer than it > stays high. I believe I just used a ceramic dip capacitor, could this be > the problem ? Apparently it's discharging faster than it's charging at low > frequencies. Also, although my LFO goes well up into the audio range, it > stops oscillating when it gets below around .2 hz. Of course I'd like the > LFO to do really slow sweeps. As far as I know I put the proper components > in. > Anyone have any suggestions ? What you may be experiencing is just the design limitations of the LFO. Although I would expect the LFO to be optimized for very low frequencies, from what you suggest, it sounds as if it was designed to serve not only as an LFO but as an additional audio oscillator. In that kind of scheme, you're finding that below its optimal low frequency end, the charge/discharge currents become imbalanced. Therefore you get the different rise/fall rates. Tony >From owner-synth-diy Fri Oct 4 16:42:02 1996 From: gstopp@fibermux.com Date: Fri, 04 Oct 96 09:38:49 PDT To: synth-diy@horus.sara.nl Subject: Re: ASM-1 up and running Regarding the LFO low end problems - three things come to mind: 1. Sucky capacitor - try using a poly-anything. Optimum value is 1uF. 2. The op-amp has an offset problem. Swap it out for another, go through your stock until you find the best one. Are you using a real TL-082? If you are, then go to (3). 3. Excess solder flux. This is one of the sneakiest evils you can fall victim to. Use Flux Remover, not alcohol. I know, special stuff, expensive cans, but it's worth it, especially in charge/discharge circuits. Good luck! - Gene ______________________________ Reply Separator _________________________________ Subject: ASM-1 up and running Author: yrrab@well.com (Barry Bernard) at ccrelayout Date: 10/3/96 11:10 PM Just thought I'd mention, I have my ASM-1 project up and running. I built it with the maximum amount of pots and jacks. Almost everything worked perfectly right off the bat. It sounds great ! I'm still ironing out a few problems here and there. One thing I recommend is soldering in the "optional" 30pf capacitor across the feedback resistor of the VCA, otherwise you will get high freq oscillation on the output of the VCA's, only at a certain control voltage input level. This can be heard as "clicking" when you modulate the VCA every time you pass that certain voltage. Adding the capacitor gets rid of the problem. One thing that has me stumped is that the with really low frequencies (like less than 1 hz), the output of the LFO seems to be asymmetrical. On the triangle wave, the rising part takes a lot longer than the falling part. On the square wave, the voltage stays low for much longer than it stays high. I believe I just used a ceramic dip capacitor, could this be the problem ? Apparently it's discharging faster than it's charging at low frequencies. Also, although my LFO goes well up into the audio range, it stops oscillating when it gets below around .2 hz. Of course I'd like the LFO to do really slow sweeps. As far as I know I put the proper components in. Anyone have any suggestions ? >From owner-synth-diy Fri Oct 4 16:54:51 1996 Date: Fri, 4 Oct 1996 12:55:50 -0400 (EDT) To: synth-diy@horus.sara.nl From: Bob Zimmer Subject: Re: ASM-1 up and running At 08:14 AM 10/4/96 +0100, you wrote: >> Just thought I'd mention, I have my ASM-1 project up and running. I >> built it with the maximum amount of pots and jacks. Almost everything >> worked Much text deleted! >> One thing that has me stumped is that the with really low frequencies >> (like less than 1 hz), the output of the LFO seems to be asymmetrical. On >> the triangle wave, the rising part takes a lot longer than the falling >> part. On the square wave, the voltage stays low for much longer than it >> stays high. I believe I just used a ceramic dip capacitor, could this be >> the problem ? Apparently it's discharging faster than it's charging at low >> frequencies. Also, although my LFO goes well up into the audio range, it >> stops oscillating when it gets below around .2 hz. Of course I'd like the >> LFO to do really slow sweeps. As far as I know I put the proper components >> in. >> Anyone have any suggestions ? > >Well, I try to avoid the ceramic cap's as much as possible... they leak >considerable more than certain other type's in the same range. When I go about >building my ASM-1's I will use plastic caps (probably polypropylene... they are >quite cheap anyhow). There are polypropylene's available at 1uF (not as cheap, >but you use up only one per ASM-1 board....). You can use polycarbonate or >polystyrene as well... mylar (polyester) should also make an improvement... I have finished my ASM-1 as well and am having different problems, but I think that mine are pilot error! (;^) I have a rack chassis on order and temporarily have assembled the panel using holes in the top of an old shoe box just to hold the parts in place to try things out! I'll put a picture (for laughs only please!) on my home page in the near future! I noticed the same low end limitation in the LFO. I did use polypropylene caps, first quality ICs and 1% metal film resistors throughout the ASM-1. I felt the slightly higher cost was worth it to make the unit as good as possible. All first quality IC's added about $6.00 over the cost of surplus, and I got the metal films for $.09 each with the ones (such as 1K and 100K) bought in quantity being under $.04 each. I think that the waveform problems are inherent in the very simple circuit design. In testing the LFO in actual CV use, I found that it is really difficult to 'hear' the 'imperfect' waveforms. The LFO range seems to be about .2Hz to 800Hz or so. I'm planning to try changing the timing cap and rate pot values along with a range switch to get into lower frequencies. If I get this working well, I'll post this and a couple of other mods on the home page when they are done. Bob >=== Bob Zimmer -- Philadelphia PA ===< >=== bzimmer@voicenet.com ===< >From owner-synth-diy Fri Oct 4 18:09:09 1996 From: gstopp@fibermux.com Date: Fri, 04 Oct 96 11:07:16 PDT To: synth-diy@horus.sara.nl Subject: Re[2]: ASM-1 up and running Well ya got me thinkin' so I took my ASM over into the lab and made some measurements.... On the low side I got an oscillation period of over a minute, with the charge time slightly quicker (maybe 10%) than the discharge time, but overall real darn slow. This was with the pot turned all the way down (wiper to ground) but since it's such a junker I suspect that there were a few ohms in there rather than 0 ohms. At about a tenth of a hertz the waveform was quite symmetrical. Top frequency was 1800 hertz. Cap used is 0.47 uF poly-something (well it looks like a little blue chicklets). I just plucked it out of a parts drawer here - maybe I can log into the HP system and find the vendor info. Op-amp is a Taiwanese TI TL082CP. The 1K input resistor on the LFO's integrator is the main frequency-determining component, other than the cap itself. A larger resistor here will shift the LFO's range lower, and a smaller resistor will shift it up. The RATE pot value is really not a factor as it is used as a voltage divider in this circuit. My boards were really really well-cleaned using way too much solder flux remover spray, and this may be the difference. I brand I used is TECH SPRAY "Flux Stripper", which appears to work pretty good. I don't use isopropyl alcohol anymore - I don't think it works as well. - Gene gstopp@fibermux.com ___________________________ Reply Separator ______________________________ Subject: Re: ASM-1 up and running Author: Bob Zimmer at ccrelayout Date: 10/4/96 10:12 AM . . . I think that the waveform problems are inherent in the very simple circuit design. In testing the LFO in actual CV use, I found that it is really difficult to 'hear' the 'imperfect' waveforms. The LFO range seems to be about .2Hz to 800Hz or so. I'm planning to try changing the timing cap and rate pot values along with a range switch to get into lower frequencies. If I get this working well, I'll post this and a couple of other mods on the home page when they are done. >From owner-synth-diy Sat Oct 5 13:19:31 1996 Date: Sat, 5 Oct 1996 15:15:11 +0100 (MET) From: "Erik The ViKing" To: synth-diy@horus.sara.nl Subject: Re: ASM-1 up and running > I have finished my ASM-1 as well and am having different problems, but I > think that mine are pilot error! (;^) I have a rack chassis on order and > temporarily have assembled the panel using holes in the top of an old shoe > box just to hold the parts in place to try things out! I'll put a picture > (for laughs only please!) on my home page in the near future! > Don't laugh now; I've done about the same thing. At least just for testing. But now I'm still wondering, as a lot of you finally seem to have got it running (like I do!), whether anyone has come up with a design for a front panel. Also: what pots did you add??? Basically my idea was: VCO: -pots: +fine tune +coarse tune +square level +saw level -jacks: +4*CV in +FM in AC +FM in DC +PW Mod. in +sync in +Square out +Saw out VCF: -pots: +freq +res -jacks: +2*CV in +Pos. env +Neg. env +4*signal in +LP out +BP out +HP out +Notch out ADSR: -pots: +attack +decay +sustain +release +ADSR level -jacks: +gate in +adsr out VCA: -pots: +gain -jacks: +pos. sig in +neg. sig in +2*VC in +signal out LFO: -pots: +triangle level +square level +rate (+led) -jacks: +triangle out +square out Glide: -pots: +glide -jacks: +CV in +CV out Noise: -pots: +random n. lev. +white n. lev. +pink n. lev. -jacks: +random n. out +white n. out +pink n. out As you can see I added attenuators at the end of each module in order to lower the number of patch-cables. It also makes the ASM-1 compatible with other modules I've built/I own! I use the power-supply as in the Formant Elektor!!! Furthermore I've added a few mixers for the output, a power switch (on the power-supply). Another question: regarding from what I've listed above could anyone give me an estimate of how big (a 19-inch) plate I would need to fit it all?? And can someone tell me what's the best layout in order of the modules; top-to-bottom or left-to-right VCO etc....????? Anyway thanks and sorry for the long message! Erik PS: I have some free web-space at hand, maybe I could put out an ASM-1 homepage. If you'd like to see one please send material to: eriks@snail.stack.urc.tue.nl >From owner-synth-diy Mon Oct 7 09:05:10 1996 From: Haible_Juergen#Tel2743 To: DIY Subject: AW: ASM-1 up and running Date: Mon, 07 Oct 96 11:00:00 PDT > One thing that has me stumped is that the with really low frequencies > (like less than 1 hz), the output of the LFO seems to be asymmetrical. On > the triangle wave, the rising part takes a lot longer than the falling > part. On the square wave, the voltage stays low for much longer than it > stays high. I believe I just used a ceramic dip capacitor, could this be > the problem ? Apparently it's discharging faster than it's charging at low > frequencies. Also, although my LFO goes well up into the audio range, it > stops oscillating when it gets below around .2 hz. Of course I'd like the > LFO to do really slow sweeps. As far as I know I put the proper components > in. > Anyone have any suggestions ? Do you have offset compensation on the opamp that forms the integrator? (posted about this a few weeks ago ...) JH. >From owner-synth-diy Wed Oct 9 11:28:56 1996 From: Erik Schuijers Subject: ASM-1 front-panel To: synth-diy@horus.sara.nl Date: Wed, 9 Oct 1996 13:28:53 +0200 (MET DST) Hi all, yesterday I've edited a design for my frontplate for the ASM-1 modular. It's become huge!!! A lot of extra pots are added as attenuators. It's 19-inch wide and eight heights. That gives a grand total of: 2*6*8=96 holes for pots, connectors and a led. I've only got room left for one hole. ALL THE OTHERS ARE USED. The only thing I added which I think is definitely lacking on the ASM-1 board is a mixer for the outputs of the VCAs. In my front-plate design I've added a 2-input mixer with adjustable gain, there just wasn't more room left for more inputs. I've also added thru ports for one of the CV's of each VCO, and the gate on the ADSR. VCO's: 2 times 2*8 holes VCF: 2*8 holes ADSR: 2 times 2*4 holes VCA: 2 times 2*3 holes GLIDE: 2 + 1 holes NOISE: 2*3 holes LFO: 2*3 holes MIXER: 2*2 holes ---------------- + 96 holes to drill!!! Later this week I'm going to make some GIF's of the separate modules which I will then put on my web-page. I've already designed a nice 'scale' ;very much like the Elektor Formant. A question about that mixer: How much decoupling would one simple two-in one-out negative amp need?? Is 1u on both sides enough and what is a good opamp for this use??? Could I use a TL-082 of which I have stacks and stacks?? Greetings Erik PS: I'll keep everyone up-2-date on what's happening! >From owner-synth-diy Thu Oct 10 21:44:09 1996 From: gstopp@fibermux.com Date: Thu, 10 Oct 96 14:44:26 PDT To: synth-diy@horus.sara.nl Subject: Re: ASM-1 Here's an example of a basic full-featured system: Pots: ------------------------------ VCO 1 Fine Tune VCO 1 Coarse Tune VCO 1 Initial Pulse Width VCO 1 Modulation Depth VCO 2 Fine Tune VCO 2 Coarse Tune VCO 2 Initial Pulse Width VCO 2 Modulation Depth VCF Cutoff Frequency VCF Resonance VCF (+) Modulation Depth VCF (-) Modulation Depth ADSR 1 Attack ADSR 1 Decay ADSR 1 Sustain ADSR 1 Release ADSR 2 Attack ADSR 2 Decay ADSR 2 Sustain ADSR 2 Release VCA 1 Initial Gain VCA 1 Modulation Depth VCA 2 Initial Gain VCA 2 Modulation Depth LFO Rate Glide (Portamento) Amount Input/Output Jacks: ------------------------------- VCO 1 Exponential FM input (4) VCO 1 Linear FM DC input VCO 1 Linear FM AC input VCO 1 PWM input VCO 1 Sync input VCO 1 Sawtooth output VCO 1 Pulse output VCO 2 Exponential FM input (4) VCO 2 Linear FM DC input VCO 2 Linear FM AC input VCO 2 PWM input VCO 2 Sync input VCO 2 Sawtooth output VCO 2 Pulse output VCF Exponential FM input (2) VCF Audio input (4) VCF (+) Modulation input VCF (-) Modulation input VCF Lowpass output VCF Bandpass output VCF Highpass output VCF Notch output ADSR 1 Gate input ADSR 1 Envelope output ADSR 2 Gate input ADSR 2 Envelope output LFO Triangle output LFO Square output White Noise output Pink Noise output Random Noise output External CV input (or multiple to send to VCO's etc.) External Gate input (or multiple to send to EG's etc.) VCA 1 (+) signal input VCA 1 (-) signal input VCA 1 Control input (2) VCA 1 output VCA 2 (+) signal input VCA 2 (-) signal input VCA 2 Control input (2) VCA 2 output The Coarse Tune pots on the VCO could be octave rotary switches if desired. You may even be able to get rid of the Fine Tune pots if you use 10-turn or 20-turn panel pots for the Coarse Tune. As for any additional controls - there's two primary approaches to modulation routing in modular synthesizers - I'll call them the "Moog approach" and the "Emu approach". The Moog approach is to put all the minimum pots on each module, and dealing with modulation depths and signal strengths (really the same thing in a true modular) by the use of attenuators and mixers on seperate panels. The Emu approach is to provide all of the minimum pots on each module, and then provide additional pots on each module as input level controls for the audio as well as the CV inputs. The modules become more complex and costly, but more self-contained. Whatever you want to do. feel free. The Emu approach will probably cost more and take up more panel space, and lots of pots will go un-used most of the time, but it sure is easy to make patches. Regarding the CV and Gate inputs - the VCO and VCF CV inputs are exponential at 1 volt per octave. The Gate input is a positive V-trigger, with the threshold adjustable on a trimpot on each ADSR to be anywhere between ground and +15 volts. There is no pulse trigger input - the ADSR's require only a Gate input (positive voltage as long as a key is held down). Hope this helps, - Gene gstopp@fibermux.com ____________________________ Reply Separator _______________________________ Subject: ASM-1 Author: Bert.Schiettecatte@hookon.be at ccrelayout Date: 10/10/96 1:54 PM Hi! can anyone tell me where I can get full building information for this beast ? Generally, what would be interesting inputs/outputs/switches/pots on a modular ? thanks in advance! Bert. >From owner-synth-diy Sat Oct 12 11:32:25 1996 Date: Sat, 12 Oct 1996 13:28:31 +0100 (MET) From: "Erik The ViKing" To: yrrab@well.com, synth-diy@horus.sara.nl Subject: Re: ASM-1 up and running Hi you all, basically my design looks like: _____________________________________ l VCO l VCO l VCF lADSR l VCA l LFO l l l l l o o l o o l * . l l l l * * l l l l l * * l * * l l * * l o o l * o l l l l o o l l l l l l l l l * o l * o l *=pot l o o l o o l o o l * * l_____l_____l o=connector l l l l l VCA lNOISEl .=led l o o l o o l o * l * o l o o l * o l l l l l_____l l l l o o l o o l o * lADSR l o o l * o l l l l l l l l l o * l o * l o o l o o l * o l * o l l l l l l_____l_____l l o o l o o l o o l * * lGLIDElMIXERl l l l l l l l l * o l * o l o o l * * l o o l o o l l l l l l l l l * o l * o l l * o l * l * o l l_____l_____l_____l_____l_____l_____l Well just imagine everything is on the same line. VCO: (left-2-right, top-2-bottom) Fine tune, Coarse tune CV IN, CV in CV IN, CV in CV thru, sync in PW mod in, init PW FM in, FM in(AC) SQ level, SQ out SAW level, saw out VCF: Freq, Q Signal in, sig in sig in, sig in CV in, tracking CV in, tracking + env, - env LP out, HP out BP out, Notch out ADSR: gate in, gate thru a, d s, r level, out VCA: + sig in, - sig in CV in, CV in Init gain, out GLIDE: CV in, CV out Glide LFO: Rate, led Tri lev, tri out Sq lev, square out Noise: White level, white out Pink level, pink out Random level, random out Mixer: In 1, In 2 Gain, Master out! I've already drawn the first module front-plate. As soon as I'll get some free time on my hands I'll put it on my web-page. Erik PS: If there's anyone who sees something definitely lacking on my choices please let me know soon! >From owner-synth-diy Tue Oct 15 09:15:35 1996 Date: Tue, 15 Oct 1996 11:14:26 +0100 (CET) From: "Erik" To: synth-diy@horus.sara.nl, analogue@hyperreal.com Subject: ASM-1 Frontplate Homepage Hi all, I've finally designed all the front-plates for the ASM-1 project. They are at: http://huizen.dds.nl/~resonant/index.htm Sorry for the REAL cheesiness but hey, I only have a little bit of time. Erik (The ViKing) >From owner-synth-diy Fri Oct 18 16:08:54 1996 From: gstopp@fibermux.com Date: Fri, 18 Oct 96 09:08:21 PDT To: synth-diy@horus.sara.nl Subject: What is an ASM-1? Hi DIY list, In order to answer the periodic questions that come up about the ASM-1, here's a snippet of e-mail from earlier this year: ************* Beginning of e-mail snippet ************************** Hi DIY List, I've had a circuit board made. I just got the prototype back and started to stuff the parts, and so far it looks like it's a cool thing. It has two saw/pulse VCO's, a multi-mode VCF, two ADSR's, two VCA's, an LFO, and a White/Pink/Random Noise Source. It's basically similar to an Oberheim SEM, except for the noise source and extra VCA. All circuit sections are discrete - in other words, no hard-to-find custom synthesizer chips! The circuits are based on the Electronotes modules that I've experimented with lately. Here's a brief description of each module: VCO - based on the Electronotes sawtooth design, with a CA3140 integrator with FET reset, controlled by an LM311 comparator. The NPN exponential converter can be an Analog Devices MAT-02 matched pair, or a pair of hand-matched 2N3904's. A 1K tempco resistor can be used for best stability but is optional. There are 6 exponential CV inputs, 2 linear FM inputs, 2 pulse width inputs, a sync input, a sawtooth output (-5v to +5v), and a pulse output (-5v to +5v). VCF - based on the Electronotes state-variable design. The exponential converter is based on one 2N3904 and two 2N3906's. The integrators are CA3080's buffered by CA3140's. There are 4 exponential CV inputs, one inverted exponential CV input, 4 audio inputs, and one buffered output each for Lowpass, Bandpass, Highpass, and Notch. VCA - based on the Electronotes 3080 linear design. There are 3 CV inputs, one (+) signal input, one (-) signal input, and one output. ADSR - my own design from a couple months ago, using an LM358 for the input comparators, a CD4002 for the attack flip-flop, a CD4053 analog switch, and a TL082. Noise Source - based on an Electronotes design. It uses a reversed-biased NPN transistor junction followed by a series of op-amp filters. LFO - typical tri-square manually-controlled design. PCB dimensions are 4.8" by 11". Power required is +/- 15 volts. I wanted to try out my CAD package and local circuit board vendors, so for the first project I decided to make something useful instead of just a single module. I would like to offer this circuit board to other people on the mail lists. I want to make a run of circuit boards and sell them, and I need feedback to get some commitments on just how big an order I should place. The more I order the cheaper they'll be. Note: I do not have any unrealistic ideas on making a huge profit here. This is my hobby and my only monetary goal would be to recoup the film and PCB setup costs (a few hundred dollars) plus some time and energy spare change. I expect that I'll be able to sell the bare boards for around $60 each. Any interest? - Gene gstopp@fibermux.com *************************** End of e-mail snippet ******************** You can e-mail me for details. >From owner-synth-diy Wed Oct 23 16:38:58 1996 From: gstopp@fibermux.com Date: Wed, 23 Oct 96 09:39:01 PDT To: synth-diy@horus.sara.nl Subject: Re[2]: more MetalPhoto info Hi list, I've been watching this thread (in its various incarnations) for a while, with great interest! I really *do* plan to build some ASM-1 project soon, honest. One good thing about letting it slide for so long is that I tend to think about it a lot and new ideas crop up now and then. Okay listen I designed the thing back in, heck, March or something and I have 3 working stuffed circuit boards, but no synthesizers yet! What the hell is wrong with me. Well my wife had a baby in March and then we sold our (undersized) house and bought a new (oversized) house in June so now I'm just starting to get back to projects. Yeah yeah excuses excuses.... anyway here's my input to this thread: If a cheap cool-looking panel were available I'd like to be in on the design (if I may) and I'd also want a bunch for myself. I've been holding off on making any commitment for anything that would cost more than $10-30 per. What's the price for this thin-aluminum glue-it-on sheet idea? It seems like I'm zeroing in on this laser-printed cardboard thing simply out of sheer cost-effectiveness plus ease. I do not want any chemical or paint messes - somebody else can do that if they want. I do want to use a PC, if I make my own. No more freehand for me, I'm past that stage. And if somebody else can do it, I would be very happy indeed as that would free up some time for the building process itself! These are my synthesizer thoughts: 1. Big panel, all fully patchable, semi-modular design (a "semi-modular" has separate sections on the panel for independent modules but you can't move them around like on a Moog). No corners cut, all possible jacks and pots, banana or 1/4" jacks. 2. Small panel, normalled connections, for "expander module" type synthsizers, like the OB SEM. 3. Medium panel, normalled connection, one set of controls for a group of ASM-1's plus some minor individual controls (like individual VCO fine tune tweaks, etc.). Of course now the cabinet behind would have to be bigger to hold all those PCB's.... The first would be good for small modulars. One more ambitious idea is to make this design, times four or eight, to get a big patchable poly monster (drool drool) with lots of patchcords. The second would be more portable. The third requires a little modification to the ASM's so that their ADSR controls and VCF resonance etc. are ganged together for voltage control. I've discovered a cool way to VC the EG time constants cheaply but it does require some added mess. As far as panel layout goes - I have a design done in Microsoft Paintbrush (I know - yuk, so I did it at work okay?) for laser-printing that has what I think is a good compromise between simplicity and completeness. It's like #1 above, fully patchable, and fits on a plate 16.5" X 12.75", which would rack-mount easily across the 16.5" dimension. That plate happens to be one that we use here at work for a lid to one of our products, so I can get scratched ones from the production floor for free, so that's where my design size came from. I figured that two of these, one above the other, in a wood case about 9" deep, would be about the same physical dimension as a Moog System 15, so I envision making three or four cabinets and setting them side-by-side for a cool n-voice modular setup. Anyway if we can make it cheap, and if it's easy to apply, and it's durable, and it's very, very cool looking, I want to be involved! - Gene gstopp@fibermux.com ______________________________ Reply Separator _________________________________ Subject: Re: more MetalPhoto info Author: Christopher_List@Sonymusic.Com at ccrelayout Date: 10/23/96 7:21 AM > This seems like a great material for front panels. Yes, absolutely. It's funny, after searching through Yahoo and whatnot for quite sometime yesterday under "printing" "engraving" "Screen printing" "metal fabrication" "maufacturing" etc, I couldn't find this. Whodda thought the keyword is "Metalphoto". I really like the fact that you can get shops to do this for you - especially when you consider the fact that many of them must be used to really small runs for awards and signs and stuff. This looks like the prime method of doing the faceplates for the ASM-1. This way we can do them in one size and people can fix them to whatever size panel theyt want and add the extra features in the blank space... Or make one bigger size and people who don't want the extra features can just cut that part off! Questions for Stew: 1. What's a recommended thickness? You don't want it too thick if you're sticking it onto 1/8" plates because the threads for the pots won't go through. 2. What's a recommended color - I think black lettering on silver would be best, but maybe reversed would look cooler? Which is more durable - or are they both tough? Thanks, - CList >From owner-synth-diy Wed Oct 23 17:38:18 1996 To: Synth-DIY , Analogue Heaven , electronica list , Bode list cc: Magnus Danielson Subject: ASM-1 Homepage release note From: Magnus Danielson Hi! First, sorry for the crossposting that some might experience. Drumroll please.... Naw, not anything fancy... I am pleased to announce that there is now a homepage for Gene Stopp's ASM-1 synthesizer board. It's basically all the material he wound send you. I know that there is a lot of people that want to peek in on what it really is. I have included some schematics even, more to come but it's just the overhead of makeing them... http://www.it.kth.se/~e93_mda/synths/companies/stopp/ Feel free to contribute with comments, tips and tricks. Please feel free to peak around on my pages at http://www.it.kth.se/~e93_mda/ Enjoy! Magnus >From owner-synth-diy Wed Oct 23 19:06:37 1996 From: gstopp@fibermux.com Date: Wed, 23 Oct 96 12:06:11 PDT To: synth-diy@horus.sara.nl Subject: Re[4]: more MetalPhoto info Gosh I knew that comment would stir up some interest.... Well I was considering using photoresistor couplers (like VacTeks) across or instead of the EG time constant pots, because I know that works great, but first of all I'm not sure how available those are still and if so they probably cost a couple bucks apiece. So first I wanted to see if there was anything I already had lying around so some gut instinct led me to the parts drawers here at work (shhhhhh...) and into the optocouplers. I picked one at random (4N37) and tried it out. It worked! The 4N37 is a six-pin DIP package, with two pins for the internal LED and two pins for the collector and emitter for the internal photo-NPN. Well if you connect the emitter to ground and the collector to a buffered cap (like the cap/buffer in the ASM-1 EG's), and charge up the cap, and put a little current into the 4N37, the cap will be discharged at a rate proportional to the LED current. Lots of current, fast discharge, no current, no discharge. Likewise if you attach the emitter to the cap and the collector to V+ and discharge the cap and put current into the 4N37, the cap will charge up at a rate proportional to the current into the LED. Lots of current, fast charge, no current, no charge. Since the ASM EG's are of the analog switch charge/discharge type, these opto's could replace the pots and you just use one control each for A, D, and R to all the respective LED inputs (the S control is already a voltage). Looks like the time constants will be from microseconds to minutes - if you put no current at all into the opto's the charge/discharge stops totally. Cool huh. I have not tried this on an ASM yet. This has only been done on a protoboard and a scope. One potential problem is the LED currents will add up if you parallel a lot of units, so a simple pot may not have enough ooomph to drive them all. More research must be done. The "mess" I mentioned would be the 3 opto's that would have to be added to the circuit board, per EG. Since there's some blank real estate next to the EG chips, I'd probably try to super-glue them upside-down to the PCB and run wires to the solder pads. This trick won't work for the VCF resonance or the ADSR depth to the VCF. Since there's an extra VCA on the ASM it can be used for one of those, and the other with an extra piggyback 3080 or something. That should make the ASM useful in polysynth designs, at least as far settings go. Selection of VCO waveforms, VCF output modes, VCO sync, and other stinky problems may have to be dealt with using relays or analog switches, so beware! - Gene gstopp@fibermux.com ______________________________ Reply Separator _________________________________ Subject: Re[3]: more MetalPhoto info Author: Christopher_List@Sonymusic.Com at ccrelayout Date: 10/23/96 11:33 AM > I've discovered a cool way to VC the EG time constants > cheaply but it does require some added mess. Please elaborate!!!! - Thanks, CList >From owner-synth-diy Thu Oct 24 20:35:43 1996 From: gstopp@fibermux.com Date: Thu, 24 Oct 96 13:34:32 PDT To: synth-diy@horus.sara.nl Subject: Re[2]: Linear current source The VCA's in the ASM-1 are designed around a concept discussed in EN#63, which is a technique devised by the famous Walter Jung in which the 3080 is used as a current mirror array in the feedback loop of an op-amp. The V- pin on the 3080 is driven by the op-amp's output. This is about the simplest way to apply an accurate linear OTA control that I've seen. Conveniently, the op-amp's (-) input is a summing node for positive control voltages. The OTA output is a current so it needs an I-to-V converter (another op-amp); however, if you are using multiple VCA's to a single destination, you only need 1 I-to-V op-amp for the lot. - Gene ____________________________ Reply Separator _______________________________ Subject: Re: Linear current source Author: Magnus Danielson at ccrelayout Date: 10/24/96 12:42 PM > Does anybody have any good linear voltage->current source for OTA > circuits that can drive the OTA over it's full range? Driveing OTAs has become a recent little problem of mine as well... In the ASM-1 there is a op-amp and two diodes that drives an CA3080 with = linear control. I haven't put that schematic on the web.... yet! Magnus >From owner-synth-diy Thu Oct 24 22:04:31 1996 From: Christopher_List@Sonymusic.Com To: synth-diy@horus.sara.nl Date: Thu, 24 Oct 1996 17:09:17 -0400 Subject: Re: Re[2]: Linear current source Magnus wrote; > In the ASM-1 there is a op-amp and two diodes that drives an CA3080 with = > linear control. I haven't put that schematic on the web.... yet! ...and Gene wrote; > The V- pin on the 3080 is driven by the op-amp's output. > This is about the simplest way to apply an accurate linear OTA control that I've seen. > Conveniently, the op-amp's (-) input is a summing node for positive control voltages. > The OTA output is a current so it needs an I-to-V converter (another op-amp); ...That's right, I had forgotten about this. One of the timbre modulators I built uses this method for voltage controlled x-fading. This is a good method, and I will keep it closer to the front of my mind for future use... Unfortunately, it doesn't work so well for 13600's! I guess I could just use two 3080's... Thanks guys - Chris >From owner-synth-diy Thu Oct 31 18:52:55 1996 From: gstopp@fibermux.com Date: Thu, 31 Oct 96 10:51:30 PDT To: bode@veda.is, synth-diy@horus.sara.nl Subject: Re: ASM-1 Construction The 2N4391 fits exactly as the silkscreen outline on the circuit board shows. The 2N4856 does NOT - at least the ones I have are metal cans rather than plastic half-cylinders so it was data-book time when I soldered them in. Regarding using the fancy matched pairs instead of the separate cheapo transistors, I still haven't got a setup I can play with! Sheeesh I designed the dumb thing and I still don't have one set up! Okay I'm working on it guys. When I do get my boards back up and running I'll do some stability testing. The LM358's are single-supply op-amps which is why I use them in the EG's as gate input comparators to drive the CMOS. I'm not sure what a TL082 will do in that location as the power pins are at +5 and ground (damn! another thing I should be able to try easily!). In all other dual-op-amp locations the TL082 works fine and is in fact recommended because it was designed using them. I take full responsibility for errors and/or omissions in the parts lists. Usually when I build something I just start flinging parts together like some kind of hypnotized robot. Thanks for the feedback! - Gene ______________________________ Reply Separator _________________________________ Subject: ASM-1 Construction Author: Dan Higdon at ccrelayout Date: 10/28/96 11:07 PM I know someone posted a message about this a while back, but I don't have it any more. How does the 2N4391 fit into the board? I assume that since the pins and the holes match up so nicely, and the components all seem to fit together easily, that it goes in the "natural" way. Is this right? (I sure hope so, or I'll get to test my de-soldering skills. :-) Also, is there any more information about using a MAT-02 instead of 2 transistors? How is the stability? Will I even notice a difference under "normal" studio usage? I haven't installed those parts yet, and I don't want to blow around 30 bucks on some MAT-02s if I don't have to. (That's 4 of them at around $7.50 each) One more thing - is it OK to use TL082s for all of the opamps? In particular, there are two kinds of opamps mentioned in the envelope generators. The LM358(?), which is used as a comparator is the one I want to replace. I must say that this is my first plate-through board, and I am impressed. Those parts installed with NO trouble, and soldering was a breeze. Just a few parts to order (the parts list was short 2 4.7uf caps, and one 0.1uf bypass in one of the oscillators), then I get to order all those pots and jacks. Eeeee! Thanks, hdan >From owner-synth-diy Fri Nov 1 21:06:15 1996 From: Christopher_List@Sonymusic.Com To: synth-diy@horus.sara.nl Date: Fri, 1 Nov 1996 16:19:49 -0400 Subject: ASM-1 Faceplates! Now taking orders! That's right folks! I'm <> going ahead with the production of faceplates for the ASM-1 project! (thanks to Stew and others who filled me in on Metalphoto). The first run will be for 50 (yes, 50!) panels. Gene has given his blessing on the layout and will be ordering 10 of them - I'll be keeping 4 for myself, so that leaves plenty for all you builders out there. The specifics; Price per panel: $20-25 (I don't know what shipping costs will be yet) Time: About 4 weeks Size: 4 rackspace (7"x19") Thickness: 1/8" total - .020Metalphoto laminated to .090plate. Holes: Rackmounting ovals only. I've done a lot of research during the past week to get the best price. Prices varied tremendously from one vendor to another - I got quotes as high as $60/panel and everything in between. I checked with everyplace I could find on the net as well as a couple of places I found in the Thomas Register - so you can trust that this is the best price around... Note that you will not have to do the laminating, it will come that way. You'll be getting a complete 1/8" panel. I have been assured that this lamination is just as good (if not better) than solid 1/8" plate. Just as permanent and better because it's; a. Cheaper b. Laterally stiffer You must drill the holes yourself for the jacks and knobs. There are cross hairs where each hole should go. The cross hairs are small enough that they will not show if you use 1/8 jacks. Panel layout is available via email as a .gif or zipped .bmp file. If someone would like to put it on their web page, I'd appriciate it because I do email through Lotus notes and sometime attachments don't come through for other people. I will be sending my order in (a check and the disk with the layout) first thing Monday morning. I am now taking orders, so reserve your panels quick! I don't need checks now - just reservations. I will ask for checks when Metalphoto says they're ready to ship the panels - that way I can send your orders out as soon as the panels arrive... - CList The panel specifics are as follows; All knobs are at least 1.4" center to center. At least .75" boarder between the sides and the first knob / jack At least .25" board between the top/bottom and the first knob/jack Jack spacing is far enough apart to support 1/4" jacks Dial markings and style are my own design, kinda modelled after the Serge stuff Controls included are; VCO (2): Course Tune Pot Fine Tune Pot FM Amount Pot PWM Amount Pot Initial Pulse Width Pot (2) 1v/Oct Jacks FM Input Jack (scaled) Sync Input Jack PWM Input Jack (scaled) Saw Output Jack Pulse Output VCF (1): Frequency Pot Scaled CV Pot Resonance Pot Input volume for input 1 Pot Output HP/LP mix Pot HP/LP or BP Switch (2) 1v/Oct Jacks Freq CV Input Jack (scaled) Audio Input Jack (scaled) (2) Audio Input Jacks (no scaling) Audio output jack VCF Note 1: The output of the VCF as set up in the panel offers a little more flexibility than the original four output VCF. You have a switch that when in one position sends the BP output to the output jack, when in the other position, it selects the output of a linear x-fade between the LP and HP outputs. The amount of x-fade is controlled by the pot. Notch output occurs whenever the pot is not panned hard left or right and will be or less to the HP or LP side depending on it's positon. This requires a <> modification to the circuit, but does not require any extra parts (actually it requires LESS parts). VCF Note 2: The scaled CV input is drawn as an "inverting scale" - this means that when centered, the cv has no effect. As you turn the scale to the left, a positive CV cause will cause the frequency to drop. Turn the knob to the right and a positive CV will cause the frequency to go up. It may be possible to do this with no extra parts - Gene and I are going to look into this. Otherwise, it can definitely be done with the addition of a single op-amp that can be glued to the back of the panel. We will send complete instructions. If you don't feel up to it, you could always just wire this as a regular scaled input and ignore the face plate marking, until you feel like "enhancing" it. ADSR (2): Attack Pot Decay Pot Sustain Pot Release Pot Gate In Jack ADSR Out Jack VCA: Initial Gain Pot Output Level Pot (2) Gain CV Jacks Normal Input Jack Inverting Input Jack Output jack Note: there's room for two output jacks so you can put both a banana jack and a 1/4" (as your final output). Scale: Scale Amount Pot Input Jack Output Jack Noise: White Output Jack Pink Output Jack Low Freq Output Jack LFO: Rate Pot Tri. Output Jack Square Output Jack Glide: Glide Rate Pot Input Jack Output Jack >From owner-synth-diy Fri Nov 1 23:07:44 1996 From: Christopher_List@Sonymusic.Com To: synth-diy@horus.sara.nl Date: Fri, 1 Nov 1996 19:01:39 -0400 Subject: Re: ASM-1 Faceplates! Now taking orders! > Are these faceplates done with black lettering on > silver metal or silver lettering on a black background? Whoops, forgot to mention that... Black lettering on silver background. > Are the ASM-1 boards still available? Gene? >From owner-synth-diy Fri Nov 1 23:35:55 1996 From: gstopp@fibermux.com Date: Fri, 01 Nov 96 15:36:09 PDT To: synth-diy@horus.sara.nl Subject: Re[2]: ASM-1 Faceplates! Now taking orders! Uhhh, let's see.... I got.... 40 of them here! Well 2 are spoken for but that leaves 38, and if I run out I can get more made. - Gene p.s. black on silver - we're going for that "Emu modular" look I guess... I like that. ______________________________ Reply Separator _________________________________ Subject: Re: ASM-1 Faceplates! Now taking orders! Author: Christopher_List@Sonymusic.Com at ccrelayout Date: 11/1/96 3:15 PM > Are these faceplates done with black lettering on > silver metal or silver lettering on a black background? Whoops, forgot to mention that... Black lettering on silver background. > Are the ASM-1 boards still available? Gene? >From owner-synth-diy Fri Nov 8 15:47:13 1996 Date: 08 Nov 96 10:44:42 EST From: John Speth <71214.3606@CompuServe.COM> To: Synth-DIY list Subject: ASM-1 LFO symmetry problem Some time ago a builder of an ASM-1 described a problem that he had with the LFO of the ASM-1 at low frequency settings. I had the same problem and decided to investigate. I found that this was due to slight mismatches in the power supply rails about ground. You can show that the charging rate of the timing cap is proportional to the input voltage of the integrator and if the output of comparator op-amp in the negative swing is different than the positive swing, you'll get different charging rates. So I thought I could use this to my advantage by being able to set the skew of the output waveforms. This was easy by simply adding a constant current adjustable with a pot to the summing node of the integrator. I verified that you can change the skew of the triangle output from + saw to - saw this way and likewise the pulse width of the square output. The only problem (and it's a biggie) is that the new skew control also affects the rate of the LFO. Ideally you'd like the rate and skew control independent. Does anybody have any ideas on how to achieve this? Also does anybody know which manufacturer of 7915/7815 voltage regulators produces the most accurate (in terms of output voltage) devices? I checked my data sheets for these and found they are allowed to vary between 14.6 and 15.4 V. I guess they are true "regulators" but not necessarily "voltage references". John Speth >From owner-synth-diy Fri Nov 8 16:17:39 1996 From: Haible_Juergen#Tel2743 To: DIY Subject: RE: ASM-1 LFO symmetry problem Date: Fri, 08 Nov 96 17:11:00 PST > Also does anybody know which manufacturer of 7915/7815 voltage regulators > produces the most accurate (in terms of output voltage) devices? I > checked my data sheets for these and found they are allowed to vary > between 14.6 and 15.4V. I guess they are true "regulators" but not > necessarily "voltage references". In the usual LFO circuits the positive and negative values of the rectangle function are also determined by the voltage drop over the opamp's output stage which can be very different for both rails, and is also temerature dependant. So even with accurate supply voltages you'd sitll have a problem. JH. >From owner-synth-diy Fri Nov 8 17:33:01 1996 Date: Fri, 8 Nov 1996 18:32:32 +0100 (MET) From: Niklas Lindberg Subject: Re: Yet another ASM-1 up and running! To: synth-diy@horus.sara.nl Hi list, I just realized that i'd forgot to tell ya'll that my first ASM-1 board is (almost) finished. And it makes lot'a noises :):) I also had the LFO symmetry problem and I found out it was (as expected) the TL082 opamp having a rather large offset voltage: 6.5mV So...I followed Gene's suggestion and measured all my opamps until I found one with a very low offset (0.1mV) and replaced the one on the board. Voila...oscillation period > 3.5 min ! (without foot resistor). If I pinched the wiper to gnd, the LFO simply stopped :-> I also got a chance to test the ADSR's with TL082 mounted instead of LM356...(since I had already mounted them by mistake :-) It does not work :( The TL082 don't seem to like input voltages near its negative supply voltage (gnd in this case) as the output swings high when the Gate voltage of the ADSR reaches gnd. More replacements :-) Everything else seems perfectly alright, except for one thing... I can't get the DC offset of the filter down ! The LP output swing +-1V (!) when the CV is varied over its full range. That can't be correct, could it ? I only matched the 2N3906s by their hfe, will that do ? Any suggestions ? / Niklas >From owner-synth-diy Fri Nov 8 20:18:02 1996 Date: Fri, 8 Nov 1996 15:19:40 -0500 (EST) To: synth-diy@horus.sara.nl From: Bob Zimmer Subject: RE: ASM-1 LFO symmetry problem At 05:11 PM 11/8/96 PST, you wrote: > >> Also does anybody know which manufacturer of 7915/7815 voltage regulators >> produces the most accurate (in terms of output voltage) devices? I >> checked my data sheets for these and found they are allowed to vary >> between 14.6 and 15.4V. I guess they are true "regulators" but not >> necessarily "voltage references". > In my power supply, I'm using LM317 and LM337 variable regulators for two reasons. First they allow me to accurately set the output voltage (at least to the accuracy of my DMM!) to match each other. Second, with the addition of two cheap capacitors on each supply, it offers 15 dB of improved regulation. Bob >=== Bob Zimmer -- Philadelphia PA ===< >=== bzimmer@voicenet.com ===< >From owner-synth-diy Mon Nov 11 06:44:31 1996 Date: Sun, 10 Nov 1996 22:58:15 -0800 To: synth-diy@horus.sara.nl From: robot@sdic.net (Robot) Subject: ASM-1 and other questions Hrm. I'm still hesitant. It's been nothing but a hassle to try and get a post through. Maybe this time it is all okay. I have a question about the ASM-1 for those of you who have built one. What would you estimate the cost of all the parts came to? Please exclude the price of the PCB and a faceplate as I plan to buy them both from Gene and Chris respectively. Also please exclude estimate of small things like wire and solder and such. I'm just interested in a rough estimate of the circuitry, pots, switches, and jacks. Another question I have is about power supplies. I have the Craig Anderton book as well as Terence Thomas's book and they both discuss building a power supply. Is it absolutely necessary to build one or is there a simpler solution of buying one? It appears that a DC power supply is the standard for audio electronics (for stability I'm to understand). Is it just as easy and possibly more secure to build my own power supplies or might it be easier to buy them pre-built with the specs needed for audio? On a similar note, I'm curious about grounding. Is it better to ground a board to the ground plug from the AC wall outlet or should I plan to ground to the chassis of the gear I build? Oh, and does anyone have any corrections of the Terence Thomas Sound Synthesis book? I'd like to explore some of the designs in there but I've been warned about mistakes and such. Also his book recommends building some test circuits to test things like transistors. Is this absolutely necessary? One last question. I'd really like to get a scope but I'm on a student budget. I'm planning on hunting for one at flea markets and such but when it comes to older OS's they get more confusing than the ones we use at school. What features should I look out for so that I can trim down my costs to the bare minimum needs for audio testing. I'm sorry for so many questions but they've been building up and I've been having the worst time trying to post. Thanks for all who help me in getting my feet wet and thanks to all on the list for providing VERY informative reading. BTW I built a Fatman for a friend and I posted my opinions on AH. I can re-post them here if anyone is interested but I'm assuming most of you are beyond that sort of project anyway. Besides I know a lot of you are on AH and most likely saw it. _ -robert | |___ ____ ____ _____ | |_ \ / -__/ / _/ | _ \ __________ |_____/ \___\ |_| | |__/ / -studio- \ _________________________________ |_| http://icse1.ucsd.edu/~rcurlee/ \ >From owner-synth-diy Mon Nov 11 08:13:25 1996 Date: Mon, 11 Nov 96 09:03:53 PST From: Tim Cockram Subject: RE: ASM-1 and other questions To: synth-diy@horus.sara.nl, Robot Several companies in the UK have tried building and selling "audio standard" power supplies. The only problem is that by the time that you have packaged them properly and safely the cost is to high for diy applications. You could use a "wall wart" to supply a reasonable ac or "dc" supply to your project and then add a good regulator within the box. A good power supply is really very important (you wouldn't believe the number of pro-audio toys that are compromised by thier PSU's). Aim for a low output impedance (the line doesn't dip if you draw more current) good regulation (this is really important if the supply is used as a reference anywhere eg the exponential converter reference current or even the front panel pitch pots!) and last but not least make sure that your grounding system is good. Tim >From owner-synth-diy Mon Nov 11 12:25:28 1996 From: Haible_Juergen#Tel2743 To: DIY Subject: AW: RE: ASM-1 and other questions Date: Mon, 11 Nov 96 13:25:00 PST > A good power supply is really very important (you wouldn't believe the > number of pro-audio toys that are compromised by thier PSU's). Often the *Noise* of voltage regulators is a problem. Drawing a reference current by a resistor from a 78xx regulated supply can ruin your SNR completely. JH. >From owner-synth-diy Mon Nov 11 13:17:53 1996 From: Paolo Predonzani Message-Id: <199611111320.OAA25515@dist.dist.unige.it> To: HJ2743@denbgm3xm.scnn1.msmgate.m30x.nbg.scn.de (Haible_Juergen#Tel2743) Date: Mon, 11 Nov 1996 14:20:19 +0100 (MET) Cc: synth-diy@horus.sara.nl In-Reply-To: <328799F4@MSMGATE.M30X.NBG.SCN.DE> from "Haible_Juergen#Tel2743" at Nov 11, 96 01:25:00 pm > Often the *Noise* of voltage regulators is a problem. > Drawing a reference current by a resistor from a 78xx > regulated supply can ruin your SNR completely. > > JH. > One solution is to split the resistor in 2 resistors in series and put a capacitor between ground and the node where the two resistors meet. This works if the resistor is supposed to be between constant voltages (e.g. between Vcc and the virtual ground at the inverting input of an opamp). -- +-------------------+----------------------------------+ | Paolo Predonzani | email: predo@dist.dist.unige.it | +-------------------+----------------------------------+ >From owner-synth-diy Mon Nov 11 18:21:56 1996 From: Troy Sheets Message-Id: <199611111821.KAA06878@xanadu.cyborganic.com> Subject: Re: ASM-1 and other questions To: robot@sdic.net (Robot) Date: Mon, 11 Nov 1996 10:21:37 -0800 (PST) Cc: synth-diy@horus.sara.nl In-Reply-To: <2.2.32.19961111065815.00692188@sdic.net> from "Robot" at Nov 10, 96 10:58:15 pm > I have a question about the ASM-1 for those of you who have built one. What > would you estimate the cost of all the parts came to? Please exclude the > price of the PCB and a faceplate as I plan to buy them both from Gene and > Chris respectively. Also please exclude estimate of small things like wire > and solder and such. I'm just interested in a rough estimate of the > circuitry, pots, switches, and jacks. My estimated expenses for the ASM-1, US dollars: board 60 on-board components 150 pots, knobs, jacks 100 19"x10.5" panal 30 Power supply 80 table-top, 19"x32" rack: 100 Banana cords, wire, misc 80 total: 620 your milage may very. -troy ------------------------------------------------------------------------------ tsheets@cyborganic.net <- You have found me tsheets@schwa.eng.sun.com <- Official Use Only http://www.cyborganic.com/People/tsheets <- Instant Content troys-list@schwa.eng.sun.com <- Inquire Within >From owner-synth-diy Tue Nov 12 19:13:41 1996 Date: Tue, 12 Nov 1996 20:05:43 +0100 From: thierry.rochebois@ief.u-psud.fr (Thierry Rochebois) To: synth-diy@horus.sara.nl Subject: asm1 dream Hello, Look at http://www.ief.u-psud.fr/~thierry/asmdream.gif and you will see the dream of many of us. Thierry >From owner-synth-diy Tue Nov 12 21:24:31 1996 Date: Tue, 12 Nov 1996 13:23:45 -0800 (PST) From: Ray Peck To: synth-diy@horus.sara.nl In-Reply-To: Subject: RE: ASM-1 and other questions Tim Cockram writes: > Several companies in the UK have tried building and selling "audio standard" > power supplies. The only problem is that by the time that you have packaged > them properly and safely the cost is to high for diy applications. Paia sells power supply kits (although Mr. Simonton is probably too modest to say so here). >From owner-synth-diy Tue Nov 19 22:42:10 1996 From: Troy Sheets To: synth-diy@horus.sara.nl Date: Tue, 19 Nov 1996 14:41:09 -0800 (PST) Subject: I powered my ASM-1 up last night... ... and a resistor smoked on the noise generator... no big deal... but both my oscillators are silent. I am checking with data sheets my transistor placement, but I can't find a MAT-02 data sheet. I took a chance and dropped these things in the way they looked like they were suppose to go, with the 3 wires on each side of the can matching up with the 3 holes in the board. Is this right? If not, can someone explain the orientation of the MAT-02s on their board? thanks! -troy ------------------------------------------------------------------------------ tsheets@cyborganic.net <- You have found me tsheets@schwa.eng.sun.com <- Official Use Only http://www.cyborganic.com/People/tsheets <- Instant Content troys-list@schwa.eng.sun.com <- Inquire Within >From owner-synth-diy Tue Nov 19 23:28:54 1996 From: gstopp@fibermux.com Date: Tue, 19 Nov 96 15:28:44 PST To: synth-diy@horus.sara.nl Subject: Re: I powered my ASM-1 up last night... Oh no, not smoke! I would guess that it was probably one of the two 22 ohm resistors at the top end of the noise generator section (near the VCF). These two resistors are used in a pair of simple R/C filters on the + and - power supply voltages to the noise gen (this is to reduce supply hum in the noise hi-gain amps). If you have a bad or backwards (shorted) 10uF cap on these filters then a resistor will smoke. The MAT-02 has a little tab on one side - this should be away from the V/OCT trimmer. Good luck! - Gene gstopp@fibermux.com ______________________________ Reply Separator _________________________________ Subject: I powered my ASM-1 up last night... Author: Troy Sheets at ccrelayout Date: 11/19/96 2:51 PM ... and a resistor smoked on the noise generator... no big deal... but both my oscillators are silent. I am checking with data sheets my transistor placement, but I can't find a MAT-02 data sheet. I took a chance and dropped these things in the way they looked like they were suppose to go, with the 3 wires on each side of the can matching up with the 3 holes in the board. Is this right? If not, can someone explain the orientation of the MAT-02s on their board?