Moog type of synth

[garcho]

For a synthesizer Behringer Model D is very cheap indeed. So cheap, I recommend reading negative reviews of it, which include "authentic" tuning drift, MIDI issues, and most horribly sounding to me, if notes are played in succession too quickly, the gate won't trigger the following note. Apparently it's bad enough people can't arpeggiate or sequence 16th notes at regular tempi. Same goes for playing a lead part, if you don't lift your finger off the former key quick enough, the following won't trigger. I'm not sure why that would happen as dealing with gate/trigger is the most basic important part of a synth after the oscillator. Perhaps firmware will help. I'm not a fan of the contemporary strategy of "to market now, debug later."

Take all this with a big grain of salt; I've never played one and haven't done much research, just the first few things I saw digging around. Some of the reviews are from a couple years ago, but from reputable sources. I try to be fair but full disclosure: I despise Uli Behringer.

[ElectricDruid]

I've had a 3320 Alfa clone guitar-oriented VCF on the breadboard for months trying to figure out how to get it down to enclosure size, what with all the bells and all the whistles. Sounds fantastic though!

Oooh, nice. The AS3320 does sound good. What power supply did you use for it? The power requirement is a bit weird for that chip.

[garcho]

±12V via ye olde LT1054, and a few key resistors. I just slapped together elements from the datasheet and the fine examples on your wonderful website.

Here's a picture of it on the breadboard, I'll put up a schematic and a few notes in a new thread. I don't think I'll be able to finish this up before I'm back in Bulgaria for the rest of the year, so it might be 2022 by the time it's boxed up and on the pedal board. I have a workshop in Sofia but I won't be bringing this along and I'll have a lot of other work to do. I plan on having mixed TH and SMD on a fab'd board. Maybe some others can shed light on it and try a few things out. I need to improve my mixed digital and analog layouts, this will be a good project for that.

[snk]

By the way, I just remembered this : The Moog Werkstatt is both Moog and DIY. It's cheaper than Behringer (their price is insane, their ethos more questionnable), should be easy to mod, enhance, etc. It features all the basic modules you need from a synth (one vco, one filter, one lfo, one envelope), along with a patchbay on the side.
I don't think it features an audio to CV converter (a used modern MS20 or a cheap Behringer MS20 module would give you the ESP for this purpose), but it couldn't be more Moog than that

[matmosphere]

I built one of these;

https://www.youtube.com/watch?v=E1Onzz76c6s

Scratched the itch a little. It certainly sounds pretty huge and it is pretty simple as far as these things go.

I have really considered the Werkstatt, it looks cool and seems to sound very good. Their stuff is solid. I have a moogerfooger ring mod and it it's built like a tank and sounds amazing. Plus I like the idea of supporting the company. On top of being an innovative genius Bob Moog seemed like a very stand up kind of guy. Leaving the business to the employees was a really cool move.

I have put the Behringer D in my cart a couple of times, but I haven't been able to pull the trigger.

[GFR]

There's this, by the same guy who designed "os Muitantes Fuzz" (Cláudio, brother of Os Mutantes' guitarrist Sérgio Dias):



Schematics, diagrams here (3 parts, "Abre_te_Cesar_CCDB_part*.pdf"):
https://aimore.org/radio/sintetizador/
Text in portuguese.



It's a multi effects , not a real synth, but the VCF is a 4th order transistor ladder. The VCF is in part 2.

Supposedly, Sérgio used it on this LP:

https://www.youtube.com/watch?v=MtsPCr0xUuw

[Kevin Mitchell]

Late to the party again 

Some folks may recall my Model D clone in the OT section. Recently that has evolved into a collaborative project. There will be a full blown Model D project soon! It'll look exactly like the classic instrument but with different PCBs and more peripherals - while being true to the classic circuit. Yes, a DIY Model D for the folks.

Alternatively, you could use the Behringer D or even better, the MME Eurorack project! Think you can find a kit on synthcube.

If you want to use these classic circuits with a guitar I suggest creating a gate trigger pedal and just patching your instrument signal into the external input. Really you'd only be utilizing the VCF and VCA unless you come up with a 1 volt per octave pitch generator for your guitar which of course would have it's own limitations without some serious ingenuity.

There's also the EH Micro Synthesizer - another DIY project I've been putting off. It has the classic functions of a synth but built for guitars.

[Mark Hammer]

The Microsynth uses an 18db/oct filter.  Is there a substantive and audible difference between 3 and 4 poles?  I don't know.

I wondered if Nova Eletronica was available on Worldradiohistory, so that the entire schematic could be seen, but could only find an Italian publication of similar name ( https://worldradiohistory.com/INTERNATIONAL/Nova-Elettronica-IT.htm ).  Figuring that various international editions of Electronics Today and Elektor often have the same circuits/projects, except only a bit out of sequence, I tried looking through the 1981 and 82 issues, but nothing so far.  I'm just speculating that the two publications were in any way linked.  But some interesting and useful circuits in the Italian one, though.

[GFR]

The Microsynth uses an 18db/oct filter.  Is there a substantive and audible difference between 3 and 4 poles?  I don't know.

I wondered if Nova Eletronica was available on Worldradiohistory, so that the entire schematic could be seen, but could only find an Italian publication of similar name ( https://worldradiohistory.com/INTERNATIONAL/Nova-Elettronica-IT.htm ).  Figuring that various international editions of Electronics Today and Elektor often have the same circuits/projects, except only a bit out of sequence, I tried looking through the 1981 and 82 issues, but nothing so far.  I'm just speculating that the two publications were in any way linked.  But some interesting and useful circuits in the Italian one, though.

https://blogdopicco.blogspot.com/2013/03/revistas-nova-eletronica-completo.html

The whole collection.

[Mark Hammer]

Excellent!  Thank you so much.  I don't speak Portugese but I gather the title of each installment is something like "Hail Cesar!"?  For those interested in the project (which does include a 4-pole ladder filter using transistors rather than diodes) it is spread across issues 55, 56, and 57.

[GFR]

Excellent!  Thank you so much.  I don't speak Portugese but I gather the title of each installment is something like "Hail Cesar!"?  For those interested in the project (which does include a 4-pole ladder filter using transistors rather than diodes) it is spread across issues 55, 56, and 57.

In fact it's "open Cesar", a pun with "open Sesame",

[Mark Hammer]

Thanks!  Just as good a title.

[StephenGiles]

I think this classic single from 60 years ago may be appropriate!!
https://www.youtube.com/watch?v=aL-hRKqqRLU

[Jarno]

Also, even though they are known for the traditional ladder style VCF, I think in their discrete VCA is also a very big part in the sound. It is a creamy overdrive-esque sound, bassy, very nice. Behringer now has these modes for little money in eurorack format, I think the vca is something like 60 euros shipped.

[StephenGiles]

I wasn't aware that a VCA affected the sound in any way other than its level??

[Mark Hammer]

Insomuch as a simple CA3080-based VCA risks distortion, I can see where that might colorate the signal.

[mdcmdcmdc]

Another option for turning your guitar/bass into a convincing mono synth with a (digital) ladder filter and some other bells and whistles is the Meris Enzo. It's expensive and the interface is a bit opaque, but if you want to just throw money at the problem it costs about the same used as any of the monosynths being suggested here. Though it is probably significantly less fun, it does do the thing and does it quite well.

Moog Rogues are still sort of cheap-ish and have a very convenient input for external audio sources as well as the ladder filter and all the other key things you want out of a moog.

[ElectricDruid]

I wasn't aware that a VCA affected the sound in any way other than its level??

Mark is right.

In the Moog synths, the VCA is quite significant for a certain distortion character. In the early Minimoogs it's a discrete transistor-based VCA circuit, and later on it's an OTA (so a soft "tanh" distortion curve) but Moog have never been afraid to drive stuff pretty hot to give it a bit of grit. That's a big part of the "Moog Sound".

[StephenGiles]

I wasn't aware that a VCA affected the sound in any way other than its level??

Mark is right.

In the Moog synths, the VCA is quite significant for a certain distortion character. In the early Minimoogs it's a discrete transistor-based VCA circuit, and later on it's an OTA (so a soft "tanh" distortion curve) but Moog have never been afraid to drive stuff pretty hot to give it a bit of grit. That's a big part of the "Moog Sound".

I stand absolutely and thoroughly corrected!!

[Jarno]

I've done a 1:1-ish clone of the minimoog vcf+vca for eurorack, without making changes to compensate for the much larger signals in eurorack, and the vca is a really nice and creamy distortion, also in the mini, there are actually two vca's in series, for the envelope and for an optional footpedal, extra creaminess

I'd suggest going with the Behringer modules, as they have shown to almost slavishly copy original schematics, but interfacing with a guitar or bass is non-trivial, it is really hard to make that sound good. My journey in eurorack started as using the modular synth as a modular effectsbox, not easy (but that was 11 years ago, a lot less was available at the time).