Modular Synth Design

[jishnudg]

So after checking out the many circuit snippets and building blocks for synth-y effects (notably Tim Escobedo's stuff) I've been wanting to make a huge modular synth,cramming all the available stuff into it (without repeating myself too much by putting in highly similar effects)..
So I thought I'd make a list of the stuff I'd put into it, the only rule being that the building blocks shouldn't be too huge in themselves.

So here goes...

1. All of Tim E.s' designs (most of them,anyway)

2. Shocktave or Slacktave (which would be better for synth sounds?)

3. Heterodyne Space Explorer (beavis audios noise generator)

Was hoping that everyone could keep adding to the list until it becomes a repository of all available synth/pseudo synth effect circuits for guitar....any suggestions?

[radio]

Here is a collection of schematics:

http://experimentalistsanonymous.com/diy/Schematics/Guitar%20Synth%20and%20Misc%20Signal%20Shapers/

[skjaldborg]

MFOS (Music from outer space) Sub Commander. Another option would be a guitar trigger and build the MFOS soundlab basically using the VCA and VCF of the soundlab to process a normal guitar signal

I haven't built one myself but I used Ray's pulse and suboctave circuit with my modular and it tracks pretty well. After that I added modules (wave shaping, lfo, VCA, VCF, ADSR, mixer  etc) from various synth forums and sites. Most of these circuits will require a +- power supply (+- 12 or 15 volts) though.

Not sure exactly what you are looking to do - a collection of synthy stomp circuits  put a modular format? or a full blown modular synth with a patch architecture etc? This stuff can get pretty huge and addictive unlike stomp boxes.........

Thing is, if you are serious about synthy sounds I think it'sworth breaking out from descrete circuits  like PWM and slacktave (good circuits that they are) and going the whole voltage controlled seperate module route it's a heck of a lot more flexible.

Paul

[Mark Hammer]

The DIY synth community is huge, and a rich repository of circuits, layouts, and ideas.  Just enter "synth DIY" into the search engine of your choice, and plug away.

Of course, your definition of "synth" may not align with someone else's.  Most keyboard or non-guitar-based conceptions of modular analog synths presume voltage controllable elements, common standards for gates or triggers, and control voltage ranges, and use of generated (i.e., VCOs or other generated voices) sound rather than processed (e.g., squared-up fuzzes) sounds.  

That doesn't mean you have to use them, just that the stompbox world tends not to mingle very much with the synth world.  Probably the closest we often get is expression pedal control.  Heck, even when something explicitly bills itself as a guitar synth, like the EHX Microsynth, or Pigtronix Mothership, they tend to be fairly closed systems, with precious little flexibility in how to route, control, or combine the different elements/sub-circuits.

I second Paul's recommendation of MFOS.  Certainly one of the other great places to start is with the folks who pretty much started modular synthesis for the DIY-er, almost 40 years ago: PAiA.  The PAiA Talk forums have a wealth of material, including scanned manuals from older products. http://www.paia.com/talk/

[FUZZZZzzzz]

some guys have been cloning the zvex tremorama.. a sequencer controlled tremolo for guitar.. my guess is this sounds awesome with synthlike pedals..  and maybe the bit crusher by experimentalist anonymous
http://tagboardeffects.blogspot.nl/2012/10/analog-bit-crusher.html

also maybe a boss slow gear clone clone for subtle attacks..

just thinking out loud

[EATyourGuitar]

don't waste your time with heterodyne peyote sphincter explorer. its a great box by itself but it is the last thing I would add to my modular synth. Mark was exactly right that most modules have standards for power, CV control, triggers, gates, audio amplitude etc and you should really research that. for DIY you should really be in a +/-15v system not +/-12v. the 12v is mostly eurorack systems that can be harder to DIY but easy to purchase modules. don't use an AC power supply, they are usually too small for the average modular system. get a real condor, power-one, meanwell, blacet, etc.. power supply wired to your mains.

the two main forums are
www.electro-music.com
www.muffwiggler.com

for kits and PCB's
www.cgs.synth.net
www.bridechamber.com
www.elby-designs.com
www.oakleysound.com/projects.htm
www.synthcube.com
www.musicfromouterspace.com

a great source of information on vintage moog DIY. this guy designed the new arturia minibrute
www.yusynth.net

more DIY info
www.timstinchcombe.co.uk/
www.uni-bonn.de/~uzs159/
www.sdiy.org

but there are many many synth related DIY pages in the google. search "synth DIY" "SDIY" "VCO schematic" "VCA schematic" "LFO schematic"

[skjaldborg]

Mark raises an interesting point about synth world and stompbox world not really mixing - I have always felt this is shame that we don't make more of control voltages and links between pedals -  it would add a lot of flexibility.

I have just completed a dual VCA pedal. Basically feed guitar in and you have 2 effects loops that can be dynamically mixed with 2 control voltages to produce the final output. I guess people don't want to mess about with control voltages and other boxes and wires on their pedal boards but I am surprised this is kind of device is not more popular because it's such a flexible option. Basically it can do Tremelo (with 1 or two oscillators). Put a pitch shift pedal in one of the effects loops and you get vibrato. It can do slowgear (with ADS - attack decay and sustain) - it can actually do more than this because you can swell in the two different effects stream at different rates so you could start off in fuzz and morph into clean. I have used a simple drum pattern circuit triggering the ADS to give rhythmic slicing like the Boss Slicer so you can have a sub octave beating in the back ground following your playing.

The only down side is that the VCAs are a little noisy but you can use one channel going high as the other goes low to cancel each out.  Kinda feel the Boss Slicer could be so much more (perhaps more options with the Midi feature?) but I suspect anything more flexible would be unsellable.

I would love to see more designs with control voltages



One key point is that the signal levels in a synth are typically a lot higher than stompboxes so be warned that you can't really put a stompbox in the middle of a modular synth setup (can go before or after)

[Mark Hammer]

Modular synthesis for guitars has run headfirst into the same wall that modular guitar effects has over the years.  With the exception of the recent console/cartridge system that Devi Ever and others have backed, manufacturers have been shy to incorporate open non-propietary systems.  We've seen stuff like the Korg PME system, or Alesis' attempt to gang multiple digital pedals together, or the snap-in modules of the LIne 6 Tonecore series, but all of these have been proprietary systems that nobody else wanted in on.

In sharp contrast, analog modular synthesis has traditionally had a couple of different standards (e.g., 0-5V vs 0-10V, S-triggers vs other types, etc.), but has been fairly open.  It has always been possible to interface modules from manufacturer X, using standard Y, with modules from manufacturer X using a different standard.  The modules themselves may or may not fit the chassis of every manufacturer, but ultimately, everything could always play together.  And since it took a large number of modules to do interesting things, manufacturers were tolerant of customers having large numbers of modules from a variety of sources.

And, without wishing to paint stompbox owners as simpletons, the average modular synth user has likely put a great more effort into learning about, and understanding, what is involved in synthesis, than your typical fuzzbox user.  The consequence would seem to be that stompbox manufacturers are shy to put out products that are seen as too complicated for entry-level customers.  Heck, if they see it as too complicated to explain to customers what to look for in a wallwart (which is why they say "Use OUR power supply"), I doubt they're going to take a chance on control inputs and complex linkages of pedals.  And from what I've been able to see, even noise-gates that have send/receive jacks tend to baffle a large constituency of users.  So, tasking manufacturers to provide the sort of support needed to nurse novice-to-middle-level customers through the baffling world of control voltages is likely to be seen as unnecessarily burdensome.

Therein lies the divide between guitar players, and synth users.

[EATyourGuitar]

Mark raises an interesting point about synth world and stompbox world not really mixing - I have always felt this is shame that we don't make more of control voltages and links between pedals -  it would add a lot of flexibility.

I have just completed a dual VCA pedal. Basically feed guitar in and you have 2 effects loops that can be dynamically mixed with 2 control voltages to produce the final output. I guess people don't want to mess about with control voltages and other boxes and wires on their pedal boards but I am surprised this is kind of device is not more popular because it's such a flexible option. Basically it can do Tremelo (with 1 or two oscillators). Put a pitch shift pedal in one of the effects loops and you get vibrato. It can do slowgear (with ADS - attack decay and sustain) - it can actually do more than this because you can swell in the two different effects stream at different rates so you could start off in fuzz and morph into clean. I have used a simple drum pattern circuit triggering the ADS to give rhythmic slicing like the Boss Slicer so you can have a sub octave beating in the back ground following your playing.

The only down side is that the VCAs are a little noisy but you can use one channel going high as the other goes low to cancel each out.  Kinda feel the Boss Slicer could be so much more (perhaps more options with the Midi feature?) but I suspect anything more flexible would be unsellable.

I would love to see more designs with control voltages



One key point is that the signal levels in a synth are typically a lot higher than stompboxes so be warned that you can't really put a stompbox in the middle of a modular synth setup (can go before or after)

what you are talking about has already been done. you just amplify your guitar signal with as much clean gain as possible till you reach 10vPP. you do not want to exceed 10vPP or you might clip in some of the modules. this solves the problem you are having with a noisy VCA. ask yourself this, do you want to patch a bunch of pedals on the floor or do you want to patch one big panel of modules that are clearly labeled and arranged properly with low noise.




then coming out of the modular you just attenuate with a 100k volume knob. so simple.

[jishnudg]

Not sure exactly what you are looking to do - a collection of synthy stomp circuits  put a modular format? or a full blown modular synth with a patch architecture etc? This stuff can get pretty huge and addictive unlike stomp boxes.........
Paul

I was looking at the Subcommander..thing is, I'm a fuzzbox user, as Mark puts it Just thinking of stepping into the world of synth and synth-esque tones...which is why Tim Escobedo's circuits really appealed to me, because of how ridiculously simple they were and their 'proof of concept' nature. So what I wanted to for my initial attempts was to build smaller modules like Tim's and then find a way to tie them in together to form a larger system, rather than order a Subcommander PCB and solder it in...and just sort of incrementally increase the complexity of the circuits until I reach a stage where I can cook up my own voltage controlled synth..
So yeah I'm looking at pseudo synth --> easy synth (does Tims PWM classify as something of the sort?)  -----> real synth

Thanks and regards,
J.

[jishnudg]

PS - sorry for disappointing anyone who may have thought I was doing anything intermediate/advanced  - just want to take this one step at a time

[EATyourGuitar]

PS - sorry for disappointing anyone who may have thought I was doing anything intermediate/advanced  - just want to take this one step at a time

synth DIY is no more difficult than pedal DIY. you can buy PCB's and paint by numbers as they say. you do not need a scope to build synth modules. I don't want to sound elitist or conformist but I honestly think you are wasting your time and money to build into an inferior format when you could already be closer to your ultimate goal of building a synth like you said. what happens if you do all this pedal synth stuff now and you build the real synth two years from now? you will have two big systems that don't talk to each other as well as having the mess of pedals all over the place. that could have been time and money spent building the modular synth you really want. you will learn more about building a synth by actually building a synth. I actually think it is harder to invent your own format and standards like you said you want to and that defeats the purpose of doing the easy stuff first doesn't it?

[Mark Hammer]

Go to my site - http://hammer.ampage.org - and look at the scanned issues of DEVICE on pages 10 and 11.  Craig Anderton provided some useful modules for modular systems oriented at guitar, and explains them in terms guitar players can understand.

[senko]

Doepfer is probably the most solid of all modular synth units I have had the pleasure of using. 
Check around this site and you'll find everything from Eurorack spacing to schematics to power supply circuits to etc.
http://www.doepfer.de/home_e.htm

[Mac Walker]

Doesn't look like it has been mentioned, but to enjoy the full benefits you will want to consider a hexaphonic pickup.....

You can wind your own (six individual coils), buy an aftermarket version, or get a bridge with individual piezo elements (and add a preamp/conditioner of course).

Basically each string is treated as its own sound source, so you can play polyphonic instead of individual notes.....

[EATyourGuitar]

Doesn't look like it has been mentioned, but to enjoy the full benefits you will want to consider a hexaphonic pickup.....

You can wind your own (six individual coils), buy an aftermarket version, or get a bridge with individual piezo elements (and add a preamp/conditioner of course).

Basically each string is treated as its own sound source, so you can play polyphonic instead of individual notes.....

the history of polyphonic guitar synth

and also this

the first link talks very briefly about the brazilian group os mutantes. madbean did a PCB called deadpool that was a monophonic version of the same circuit used in the hexaphonic os mutantes guitar.

[Lurco]

Doesn't look like it has been mentioned, but to enjoy the full benefits you will want to consider a hexaphonic pickup.....

You can wind your own (six individual coils), buy an aftermarket version, or get a bridge with individual piezo elements (and add a preamp/conditioner of course).

Basically each string is treated as its own sound source, so you can play polyphonic instead of individual notes.....

the history of polyphonic guitar synth

and also this

the first link talks very briefly about the brazilian group os mutantes. madbean did a PCB called deadpool that was a monophonic version of the same circuit used in the hexaphonic os mutantes guitar.

The marked link won`t work.

[FUZZZZzzzz]

I thought this guy just wanted to put a shitload of guitar effects in one enclosure with wooden sidepanels and call it modulair. Isnt it easier just to run the guitar effects of 9 volt? and make it jack patchable?

You guys have nice ideas though! if only I wasnt working on 20 things a time!

So after checking out the many circuit snippets and building blocks for synth-y effects (notably Tim Escobedo's stuff) I've been wanting to make a huge modular synth,cramming all the available stuff into it (without repeating myself too much by putting in highly similar effects)..
So I thought I'd make a list of the stuff I'd put into it, the only rule being that the building blocks shouldn't be too huge in themselves.

So here goes...

1. All of Tim E.s' designs (most of them,anyway)

2. Shocktave or Slacktave (which would be better for synth sounds?)

3. Heterodyne Space Explorer (beavis audios noise generator)

Was hoping that everyone could keep adding to the list until it becomes a repository of all available synth/pseudo synth effect circuits for guitar....any suggestions?

[Mark Hammer]

Some writers/thinkers make a distinction between guitar synthesis and guitar processing. 

The former uses the guitar as a 6-source controller, and yields a "code" of some form, representing the properties of the picked string.  That could either be something like a MIDI code, or something like a voltage proportional to the pitch of the note picked, another reflecting how hard it was picked, and another reflecting when the string is "active" rather than functionally silent.  This information, whether digital or analog, is used to control other devices.  The sound produced is not the gutar's sound, necessarily, but somethng directed by the guitar.

With guitar processing, there is no real distinction made between the strings, or even between notes.  The guitar's role is first and foremost to indicate the onset of a musical event. The most straightforward examples of that approach are the highly familiar autowah, and to a lesser extent, swell pedals like the Boss Slow Gear.  In both instances, a transformation of the guitar's sound is going to take place, in a way which has an identifiable "beginning".

Both true synthesis and processing can make use of analog modules configured in this sequence/relationship or that.  Of course where synthesis might have additional coded information available to produce more complex outcomes (e.g., a swept filter that is adjusted to suit the pitch of the note played such that it trims the same harmonics of each fundamental, rather than just having a fixed starting point), the capacity of processing to yield such complex outcomes may be more limited.  And, I suppose it goes without saying that when the guitar is processed as a whole, rather than as 6 individual strings, you don't require as many modules.

There can be systems in between, as well.  A decade back, I had a visit by Harry Bissell, and several other DIY luminaries, to my basement.  Harry brought his "Muffy" gutar synth/processor.  It did not do any pitch-to-voltage conversion, but it did use a hex pickup, ran each string through a heavy fuzz, and provided independent envelope followers, filters and envelope generators for each string such that the guitar sound was processed in more complex fashion.  It was a remarkably expressive and responsive setup that maybe one day I'll be able to duplicate witht he spare GK-1 pickup I have.

The takehome message here is that there is a vast spectrum of ways in which synth-type modules could be employed; some more reminiscent of a Rick Wakeman / Keith Emerson "wall 'o Moog", and some which are only juuuuusst a little more advanced than the average pedalboard.  The trick to making flexible use in a way that you see fit is to have a system that is as open-ended as possible.  Though not officially designated as the "best", the AMS-100 module in the first issue of DEVICE provides a nice unit for deriving a reliable envelope follower and note onset indicator, that is optimally suited for guitar.  If you can tell other modules that "this event starts NOW", you are usually halfway home.

[jishnudg]

Thank you, Mark and everyone else who've put up their thoughts and suggestions...yes, when I  started this thread I was looking for quasi - synth sounds from effect pedals rather than true synth applications,but now after checking out some of the links put up,I think I have a fair bit of reading to do
Thanks again,
J.