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2026-03-18 by Thomas Hudson
Unfortunately this solution didn't work. I built this synth and he had to add three to four trimmers, all of them interacting to tune the thing. It was doable and I was able to get tracking pretty good. Perhaps things have gotten better, but from experience it took some tweaking.
2026-03-17 by David Manley
It's interesting to see how PAiA's John Simonton solved some these issues in the 1970's by having a custom laser trimmed resistor network built for their 6-bit "Equally Tempered DAC" to be used with linear VCOs. See the bottom of the schematic on page 18, the resistor values are
2026-03-17 by Oren Leavitt
If the real deal is unobtainium, seems like you can probably make a "daughter board" substitute with a dual OTA/VCA (LM13700, 2164, etc) and an inverter/buffer. On 3/17/26 11:00 AM, Jean-Pierre Desrochers via Synth-diy wrote: > I have a 30 years old Marshall preamp (JMP-1) that n
2026-03-17 by Thomas Hudson
UTSource (www.utsource.net ) is a US supplier for old parts. I’ve never order from them, but they have pretty positive reviews on diyAudio. They have it in stock: https://www.utsource.net/itm/p/1859728.html M5201P | In Stock | Utsource utsource.net > On Mar 17, 2026, at 12:00 PM
2026-03-17 by jpdesroc@oricom.ca
I have a 30 years old Marshall preamp (JMP-1) that needs M5201P (or substitute NJM2102D) 8 pins DIP switchable opamps. These are obsoletes and I can only be found on eBay from China suppliers (Fake ones ??) Any good USA suppliers or someone have some for sale ? Thanks.
2026-03-17 by Tom Wiltshire
While you might not need 8 or 10 octaves at once to play a melody, many V/Oct analog synths *do* have a lot more than five as a continuous range. Arguably that's a problem, since it makes the tuning issues worse and it necessitated the High Frequency Trimmer, but that *is* how it
2026-03-17 by Roman Sowa
The whole idea of 3340 existing is its temperature compensated expo converter. Not using that leaves you with simple integrateor, current mirror and switch. And waveshapers of course. This would be rather an overkill and waste, considering you can have good linear VCO very cheapl
2026-03-17 by Mike Bryant
I always used linear VCOs in my designs in the 1970s. I think the key to them, at least then, was they were accurate. Exponential convertors weren't really that good back then. ________________________________ From: Synth-diy on behalf of Adam (synthDIY) Sent: 16 March 2026 22:11
2026-03-17 by Thomas Hudson
Researching a bit more, I discovered the Yamaha CS-80 (my ultimate) had linear oscillators. > On Mar 16, 2026, at 6:11 PM, Adam (synthDIY) wrote: > > > >> On 17 Mar 2026, at 02:01, Roman Sowa via Synth-diy wrote: >> >> who needs 8 or 10 octave continuous tuning range anyway? >> N
2026-03-16 by Adam (synthDIY)
> On 17 Mar 2026, at 02:01, Roman Sowa via Synth-diy wrote: > > who needs 8 or 10 octave continuous tuning range anyway? > No analog synth has more than 5 and today most popular is 3-4. > That means smaller range is enough and you can add octave switch as separate control to cove
2026-03-16 by Terry Bowman
> On Mar 15, 2026, at 11:09 PM, Eric Frampton wrote: > > Juergen Haible Living VCO’s do this. > It’s strange hearing the beat rate stay constant, ain’t it?! He also had a linear detuning mod for the SEM-1. Terry Bowman, KA4HJH "The Mac Doctor" https://www.astarcloseup.com "Every
2026-03-16 by Thomas Hudson
One more question. I have a couple of vcos based on the cem3340, which as a linear FM input. Assuming I could generate an appropriate voltage source, could I drive them through this input? > On Mar 16, 2026, at 12:01 PM, Roman Sowa via Synth-diy wrote: > > Your point is valid, bu
2026-03-16 by Roman Sowa
Your point is valid, but rises fundamental question: who needs 8 or 10 octave continuous tuning range anyway? No analog synth has more than 5 and today most popular is 3-4. That means smaller range is enough and you can add octave switch as separate control to cover all frequenci
2026-03-16 by Tom Wiltshire
That's a thought-provoking point of view, Roman. I thought the fundamental problem with linear VCOs was that it's hard to cover an 8 or even ten octave range in a linear fashion - that's 256 or 1024 times the base value. For a CV, that requires very small offsets at the bottom. S
2026-03-16 by Roman Sowa
IMHO linear response VCOs are simply better and easier to use. No temperature dependency by design and easier to tune - as long as all offsets are small or trimmed, whatever you do, an octave is always an octave, not like with exp VCO where you have to turn 3 to 5 trimmers in sev
2026-03-16 by Robert King
I've been playing around for years with the linear oscillators from the Moog Taurus pedals , like you , I love that chorusing sound they give . I shoe-horned the octave switching circuit from the ETI 4600 onto the front to give more range and coupled 2 or 3 of them to a Korg MS s
2026-03-16 by Eric Frampton
Juergen Haible Living VCO’s do this. It’s strange hearing the beat rate stay constant, ain’t it?! Sent from a device with tiny keys. On Mar 15, 2026, at 10:52 PM, Thomas Hudson via Synth-diy wrote: My first modular synth was a Paia 4700/j synth. Yes I know, cheesy design, but t
2026-03-16 by Thomas Hudson
My first modular synth was a Paia 4700/j synth. Yes I know, cheesy design, but the one thing I miss is how linear response VCOs have a very different detuned chorusing effect with each interval. Just wondering if anyone has experimented with this?
2026-03-10 by Maffez Synthmods
Hey, I don‘t think that there are any PA397 datasheets floating about publicly but by the looks of it (using a Tetra PCB), the AS3397 could fit. https://www.cabintechglobal.com/pdf/ALFA_RPAR_AS3397.pdf https://en.audiofanzine.com/analog-synth-rack-sound-module/dave-smith-instrume
2026-03-10 by Florian Anwander
Hello, a friend asked me to have a look at his DSI Evolver Desktop. I did a search on the web but did not find any service manual for this synth or datasheet of the PA397 datasheet or at least pinout of the IC. Does anyone have info on this? Is the Alfa RPAR AS3397 compatible? Be
2026-03-06 by Michael E Caloroso
Jim Cooper made some great MIDI tools. I have three MSB+ in my studio system, they are an underrated powerful tool. Sad that the company is being liquidated. MC On Wed, Mar 4, 2026 at 11:38 PM drheqx via Synth-diy synth-diy@synth-diy.org > wrote: That's sad. I love all my JLCoope
2026-03-05 by drheqx
That's sad. I love all my JLCooper gear. Jim Cooper made some very innovative products that were well built. Mike On Wed, Mar 4, 2026 at 11:32 PM TERRY SHULTZ via Synth-diy synth-diy@synth-diy.org > wrote: Hi guys, I spoke with JL Cooper HQ! Today about some JL Cooper products an
2026-03-05 by TERRY SHULTZ
Hi guys, I spoke with JL Cooper HQ! Today about some JL Cooper products and Asked to speak with Jim Cooper. It seems Jim passed away on January 3rd, 2026. Jim hired me to work at Oberheim in Santa Monica and we have been friends for close to 50 years. The business is being liquid
2026-03-05 by Donald Tillman
On Mar 3, 2026, at 1:58 PM, Mike Beauchamp wrote: > > > Maybe take all of the different noises, and feed them into an interpolating scanner circuit (like this one: https://till.com/articles/scanner/ ) and from there you could control the output noise colour (and anything inbetwee
2026-03-05 by marc bareille
Hello Terry , I am still here. I redesigned pcbs for both Vumeters ( 2252 and 4301) many years ago, under Kicad . Double sided gerber , stereo only . Video of a complete module here https://www.youtube.com/shorts/v-DcO_LF344 3D picture of the pcb attached at the end ofthe email.
2026-03-04 by Tom Wiltshire
There's a similar heavily-filtered noise source ("infra-red" noise) in the Polyfusion synth schematics. One problem with this way of generating this type of wandering modulation voltage is that the voltage level is heavily reduced on average, but adding gain to bring it back up i
2026-03-04 by Michael E Caloroso
Few people realize that the venerable Minimoog includes red noise. But it's a modulation source not audio. The front panel NOISE switch alternates between white and pink noise as an audio source, and also between pink and red noise as a modulation source. Red noise as a modulatio
2026-03-03 by Thomas Hudson
BTW, while researching creating green noise I came across a website for a Mac and iOS app: https://simplynoise.com/ In addition to noise colors, t also has beach sounds, fireplaces, babbling brooks, etc. Fun little app. > On Mar 3, 2026, at 5:56 PM, Thomas Hudson via Synth-diy w
2026-03-03 by Thomas Hudson
Interesting idea and article. > On Mar 3, 2026, at 4:58 PM, Mike Beauchamp wrote: > > Hi Thomas, > Maybe take all of the different noises, and feed them into an interpolating scanner circuit (like this one: https://till.com/articles/scanner/ ) and from there you could control the
2026-03-03 by Mike Beauchamp
Hi Thomas, Maybe take all of the different noises, and feed them into an interpolating scanner circuit (like this one: https://till.com/articles/scanner/ ) and from there you could control the output noise colour (and anything inbetween) with the wandering CV. I wonder if the dif
2026-03-03 by listmail@misw.us
So today I'm launching the OS-303 processor. This is the first open source u650 work alike for TB-303 and TR-606/TR-808 down the road. The code has a bit to go but the core framework is there. If anyone wants to contribute, get in touch since i have development kits available. ht
2026-03-03 by Tom Wiltshire
Notice that the triangle wave, the sawtooth wave, and the psuedo-random binary level noise uniform distribution (Phew! What a mouthful!) all have the same uniform probability distribution. > On 3 Mar 2026, at 12:49, mark verbos wrote: > > I don’t know if this answers any question
2026-03-03 by rburnett@richieburnett.co.uk
You start to hear the difference at extremes... The attached WAV has 2-level (digital) noise but now with very sparse positive pulses. (Low 97% of the time. High 3% of the time.) The long-term power spectral density is still that of "white noise", the same as the previous example
2026-03-03 by mark verbos
I don’t know if this answers any question, but it is interesting. It explains why Buchla sampled a triangle wave hard synched to noise rather than sampling noise in the Source of Uncertainty. Mark
2026-03-03 by Tom Wiltshire
+1 agree with Richie and Brian. The "noise colour" (frequency spectrum) and amplitude distribution are independent. It kind-of blew my mind when I first discovered this, since (in my head at least) you'd have thought that such a significant difference in the signals would be audi
2026-03-03 by rburnett@richieburnett.co.uk
If the ZIP attachment makes it through it contains five examples of "white noise" created with different amplitude distributions: 1. Gaussian distribution 2. Uniform (all amplitudes equally likely) 3. Triangular distribution 4. Two discrete levels (Digital PRBS) 5. Three discrete
2026-03-03 by brianw
The probability distribution of the values in a random sequence are completely independent of the frequency spectrum of those values as a signal. First order probability distribution is uniform, and this is what the simplest mathematical computer noise sources produce. Second ord
2026-03-03 by Thomas Hudson
Yes very much different. There’s an old article in Scientific American by Marvin Gardner, that shows that music statically follows 1/f or pink noise. Note selection by red or brown noise is very boring. Imagine you have a random set of five dice to select the next note. Red / bro
2026-03-03 by Emily Straight
is there any statistical difference between different colors of noise after going through a sample-and-hold? i'd figured on longer timescales every possible voltage is equally likely anyway, so you wouldn't be able to tell the difference. On Mon, Mar 2, 2026, 3:26 PM Thomas Hudso
2026-03-02 by Thomas Hudson
I have an analog module that can generate blue, white, pink, and red (brownian) noise. I’m interested in how I might create a random walk using perhaps a sample/hold and smoothing function to produce a sort of wandering control voltage from each of these noise sources. I also was
2026-03-01 by Adam (synthDIY)
Sounds to me like you need a multi channel analogue desk with some aux channels and subgroups, you hang a bunch of cheap digital delays off the auxs, turn them up to max feedback, feed the aux outputs back into a few desk inputs and put whatever sound source you like on the other
2026-03-01 by Thomas Hudson
Other elements I have been experimenting with are subtle stereo flangers and phasors. The big one I’m really interested in is HRTF (head related transfer functions). I want the headphone listener to believe they are in the sound, revolving around them. > On Feb 28, 2026, at 6:44
2026-02-28 by drheqx
Envelopes!!! Samples and oscillators. Granular synthesis engine. Stuff like that. Lots of envelopes to control filters and amplitude and also panning. All at the same time across multiple sources. On Sat, Feb 28, 2026 at 6:45 PM Thomas Hudson thomas.hudson7@icloud.com > wrote: Th
2026-02-28 by Thomas Hudson
That’s all I’m looking for. What are the elements of good, evolving textures? And how can I make something similar. > On Feb 28, 2026, at 6:40 PM, drheqx wrote: > > My bandmate has it. Feature rich. Hard to duplicate but possibly emulate > > On Sat, Feb 28, 2026 at 4:29 PM Thomas
2026-02-28 by drheqx
My bandmate has it. Feature rich. Hard to duplicate but possibly emulate On Sat, Feb 28, 2026 at 4:29 PM Thomas Hudson via Synth-diy synth-diy@synth-diy.org > wrote: "I’m buying this only to duplicate it.” Should I have said Duplicate It Yes? On Feb 28, 2026, at 2:33 PM, Michael
2026-02-28 by Terry Bowman
> On Feb 28, 2026, at 12:57 PM, Oren Leavitt via Synth-diy wrote: > > Cool! > That looks tempting to me. I have a couple of those THAT4301 analog > engines that I bought some years ago. I was originally intending to > build a vocoder around THAT4301s but the chips were discontinu
2026-02-28 by Thomas Hudson
"I’m buying this only to duplicate it.” Should I have said Duplicate It Yes? > On Feb 28, 2026, at 2:33 PM, Michael E Caloroso wrote: > > This is SDIY, not Gearspace. > > MC > > On Fri, Feb 27, 2026 at 8:46 PM Thomas Hudson via Synth-diy > wrote: >> All your suggestions were awes
2026-02-28 by Michael E Caloroso
This is SDIY, not Gearspace. MC On Fri, Feb 27, 2026 at 8:46 PM Thomas Hudson via Synth-diy synth-diy@synth-diy.org > wrote: All your suggestions were awesome. I’m buying this only to duplicate it. The Soniceware Liven Ambient 0. Four layers; drone, pads, atmosphere, and noise. I
2026-02-28 by Oren Leavitt
Cool! That looks tempting to me. I have a couple of those THAT4301 analog engines that I bought some years ago. I was originally intending to build a vocoder around THAT4301s but the chips were discontinued. On 2/28/26 10:50 AM, Terry Bowman via Synth-diy wrote: > Does anyone hav
2026-02-28 by Terry Bowman
Does anyone have the PCB art for this? http://m.bareille.free.fr/vu-in13/vumeter_in13.htm I have a pile of IN-13s and I’d love to build one. Laying out a board is beyond my capabilities. Is Marc still around? Terry Bowman, KA4HJH "The Mac Doctor" https://www.astarcloseup.com "I’v