Thinking about leaving stompbox format + modular "guitar" synth question

[WhenBoredomPeaks]

I've made a few synth style circuits (for my guitar) and now it is time to box them up.

So far i have a few LFOs, a 4 channel (DC) Mixer for mixing various signals, a 4channel splitter, some filters (2 different Korg MS10s and gonna etch a pcb soon for a Polivoks and a Moog ladder filter, and probably i would incorporate the MeatSphere circuit for it's BP and HP modes and it's envelope follower)

Basically i imagine the whole thing as a modular synth without an oscillator section (that would be the guitar)

Now i think the lot of different connections ain't suit the stompbox format. Think about this signal chain: guitar comes in, it gets splitted, one signal goes to a trigger generator the other goes towards the filter. Then the trigger signal goes to an ADSR generator which is connected to the filter. Meanwhile an envelope follower which gets it's envelope from the clean signal is controlling a VCA at the end of the chain. Then it goes to whatever blabla... Meanwhile various LFO signals are getting mixed together and stuff... The different patch cables would be all over the place. And maybe later i could incorporate a real oscillator for "real" synth tones.

Would it make more sense to build most of these stuff in the modular synth format? Is that thing harder to get into than drilling hammond boxes?

Oh and what module would you put into your dream synth chain?

I will have to make an ADSR generator, (more like two) a VCA, then something which can make a trigger signal when my guitars signal is strong enough, (pick attack) then that level shifting circuit in my previous topic (so the various controls signals of different formats can work together)

Yeah don't forget the Oscillator, before this chain i would use a pitch shifter (Behringer US600, for the lower octaves mainly) and one of my various fuzzes to make a "saw" wave. What would you use for generating some waveform from the guitar signal? Are there diyable analog low octave generators with good tracking? I don't care if they are not sounding clean.

edit: i corrected some word mistakes, i used the word LFO instead of oscillator more than once

[Earthscum]

I'm working on a similar project and hitting the same wall of questions. Basically, I've decided to go with a multi-effects type setup, but that is just for foot controls. Then I will have a rack that sits up higher with most of the artwork inside of it. Basically, I'm going to attenpt a console with remote foot controls, including a couple treadles and a couple rubber "kicker wheels".

One of the ideas I've contemplated is setting a couple extra switches to be "general" switches (S1, S2, S3, or something) so that I can route to them as gates or triggers. I was originally going to use MV-52 and set 4 momentary switches in a diamond pattern to "wobble" on Bass, but I may be skipping that idea. I'm trying to stuff alot of crap into a relatively small package, lol... it's what I'm good at.

You should keep an eye on Artifus' thread "synFUZZsizer". It's gonna get a bump as soon as I get some bugs worked out of this design on my board. 

[artifus]

gone but not forgotten... there are still portions of that taking up valuable breadboard space... i've since found the electrax synthax-100 pdf and realised i was just cmos'ing those and various other past ideas... like i said, not forgotten but the problems you have highlighted have had many a head a scratching. maybe just put it in a cartridge? 

[Mark Hammer]

Once you go modular, there is no end to the modules you can find interesting to include.  In which case you need a more open system.  Folks in the synth world have pretty much settled on frac-racs of different standards as a way of expanding their processing and signal routing.
Here's what I did.  Vry simple DIY cab format, made to suit a bunch of face plates I bought cheap.  Some angle aluminum to screw them into for mounting, a power supply around back, and away you go.  No reason you couldn't score yourself a bunch of aluminum or other faceplates, pop some holes, do some legending, and create an army of modules that can be reconfigured however you want.  I settled on a 1/8" mini phone jack standard, but you could opt for whatever you want:

[artifus]

@mark - do you have a separate switching box/foot controller for that monstrosity? kudos, by the way.

[Earthscum]

That's the limitation to using guitar as an oscillator: you start realizing parts that you can just ditch because you have to keep triggering your oscillator, tying up both your hands with a "Triggered VCO" of sorts. I find modules that sound really awesome, that you realize you would have too many foot controls to make it do that (sweeps, dual sweeps, etc etc).

I keep finding myself getting too many controls going just on the "PCO" (Player Controlled Oscillator)    I tried limiting myself to only how many switches and pots I have on hand right now... forgot I ordered a bunch of 6mm DPDT pushbuttons. Now I finally got it narrowed down to Square/Smooth (secondary switch: Saw/Triangle, or a diode/pot combo for shaping), and volume.

BTW, Mark... I remember you mentioning something about the Harmonic Energizer some time back, and it didn't sound like you were all that impressed with it as far as any kind of "WOW!" factor... throw some squares into it. Synth sounding, sawtooths... nice clean stuff, not fuzzy. I think you might get a grin out of what it does... and no muffles, nice clean sounding tone. I finally got one together and played with it. I used the buffered output to send to a Sewer Pipes (since I have it breadboard ready), and it blew my mind. Using the buffer out for effects parallel and making the box true-bypass could be way more useful for that effect.

[WhenBoredomPeaks]

@Mark: Looks awesome, i think i will do that, only with some taller modules (probably this size: http://www.synthesizers.com/q131.html)

@Earthscum:

I don't worry too much about the VCO, when i am not using a guitar i will just connect it to my computer where i could run like 100 instances of ReaSynth at the same time. Hopefully waveforms are just waveforms and a digital saw ain't differs too much from an analog saw. (ReaSynth is more like a poliphonic oscillator than a real synth, it uses really minimal CPU resources)

[Mark Hammer]

@mark - do you have a separate switching box/foot controller for that monstrosity? kudos, by the way.

I had made some CMOS (4016-based) switches from the Anderton EPFM book, but need to finish hooking them up.  You can see a module with yellow legending.  each of those has two non-dedicated switching circuits that are controllable remotely via a planned footswitch (what the plastic phone jack is for).  The nice thing about the Anderton switches (which is likely easily emulated by many other circuits too) is that I can wire up a pair of parallel SPST footswitches for each "actuator", one for momentary and one for latching.  The fact that the modules are nondedicated means that I can patch in whatever I want, and nest switches within switches.  So 4 such switches (2 modules) could allow for loop C nested within loop B, which is in turn nested within loop A, and the 4th switch used to select an entirely distinct loop that could be one circuit in series at the beginning, or end, or in parallel.

There are two splitter/mixer modules for use of parallel processing.  Each sends two outs from a mono in, and has two mixable receives for a mono out.  And, because they are also nondedicated, if one wanted to get superduper crazy, the splitters could even be cascaded so that output B of one splitter goes to a second splitter to achieve 3 outputs and mixable returns.  And, of course, you can insert one of the nondedicated momentary/latchng switches in that path.

A LOT of flexibility in a very small package.  I made myself a 2U rackmount unit with a vastly-reduced set of effects (all EPFM modules) 25 years ago, that included only one nondedicated switch (maybe two, it WAS an awfully long time ago) and a single splitter/mixer.  That allowed me to incorporate  external effects and do parallel processing.  For instance, I liked to split the signal, and feed the guitar separately to a delay and a fuzz+parametric.  Mix the delay to all wet, and blend in the clean repeats with the distorted guitar using the onboard mixer.  I would insert the switch between the splitter output and the delay unit, so that I could "punch in" to the delay using either the latching footswitch, or the momentary.  Briefly feeding the guitar to the delay line, but leaving the delay's output patched into the mixer gave me what is currently referred to as "trails" or "tails" in contemporary digital-delay parlance, but with an analog delay....and 25 years ago.

I can't recommend a mini-modular frac-rac system with patching options highly enough.  Should someone be able to apply PICs or Arduinos and relays to such a thing, there' s no limit to what's possible.

Now what we need is a source for guitar appropriate face plates and predrilled mounting brackets.  My own unit was prompted, oddly enough, by a surplus place near me selling those pre-drilled black anodized faceplates 4 for a dollar, some 6 or 7 years ago.  I bought a few dozen, thinking "Hmmm, I'm sure I'll come up with some use for them eventually."

[petey twofinger]

that is really cool mark .

[Mark Hammer]

Thanks, Pete.  I should probably mention that for a little while, I was able to buy discontinued mini phone-jacks cheap when the Canadian Radio Shack decided to clear out stock.  A dollar store near me also sold dual-mono male-to-male mini-phone patch cables for a dollar, so I could buy a couple of them, peel them down the middle to separate the two male-to-male cables, cut a section off the end and attach another mini-plug to make patch cables.  using toggles, where the bat handle position shows you the state (bypass/effect) meant I could forego status LEDs, and make do with DPDT toggles, freeing up panel space.

There is a whole lot that becomes cheaper and easier to do when you go modular and create your own standard.  The modular approach that Devi Ever has been discussing/describing here in recent weeks takes a few steps in that direction, but is a little less open-ended in my view, chiefly because it still adheres to a floor-pedal paradigm.  That is not inherently wrong, mind you.  It serves an important niche.  But for those of us who don't gig, there are other horizons.

[R.G.]

See: http://geofex.com/Article_Folders/FXRack/fxrack.pdf

The steel sections can be laid parallel and screwed together to make more rows; also, one could use fittings to make them fold together face to face, etc.

And 18Ga steel is ... tough.

[boogietone]

A PIC/Arduino approach for switching and control from the floor would be my 2cents.

[boogietone]

See: http://geofex.com/Article_Folders/FXRack/fxrack.pdf

The steel sections can be laid parallel and screwed together to make more rows; also, one could use fittings to make them fold together face to face, etc.

And 18Ga steel is ... tough.

... and tough to cut.

Also, I have not been able to find any of these studs and I have looked. All I seem to be able to get my hands on are the flimsy, thin aluminum ones. My brother has some pieces left over from a construction project, but getting them to my house is a problem.

[Mark Hammer]

Another option is the predrilled/pretapped rails for rack panels, like these: http://www.rackmounts.com/Middle-Atlantic-RRFXX-DF2194.html

All you need to do is mount them across, rather than vertically, built a cabinet around it, and get some plates that will straddle the rails.  Pop some holes in the right place, and use commercially available thumbscrews to attach modules to the rails.

[boogietone]

^^^ That is a great idea.

A quick search shows that this has not been mentioned for a source of metal. http://www.metalsupermarkets.com. They have local outlets and most reasonable sized cities will have something similar for pickup. You get a discount if you rummage through their waste stack. You can pick up some plates of aluminum that could be used for attaching to the rails.

[StephenGiles]

That Mark - to quote Eddie Cochran, is "Somethin' Else"!!