Modular (Synth) Approach to Guitar Pedals

[Floyd Pepper]

I've been thinking about building a Vanishing Point recently and was wondering what I'd connect it to.  Two obvious choices would be the Tremulus Lune trem and McMeat envelope filter I've recently built.  Rather than rebuild the effect part of these circuits it occurred to me that what I needed was a modular synth approach.

If I'd built the Lune as two separate circuits - LFO & trem and the McMeat as envelope follower & filter - then I could hook a Vanishing point up to either of them.  I could also LFO the filter or envelope follow the trem.  Or put the LFO into the delay time of a delay, etc.

Anyone tried this approach?  The only downside would be a pedal board that looks like an explosion in a spaghetti factory.

[Seljer]

Moog has made those neat Moogerfoogers which had outputs/inputs for control voltages assignable to most parameters. So its not something new.

[Processaurus]

I've been thinkin about this idea for a while, it really makes sense, like you could make one nice envelope detector, be able to use the same LFO for different effects, like you were saying one sequencer you can hook up to a bunch of stuff, one power supply, etc.  Also a lot of digital pedals use normal pots to generate a control voltage that gets read by a ADC and then goes on to the microprocessor, so any of those parameters could be controlled externally by removing the CV from the pot's wiper and replacing it with whatever you want.  I'm going to do that with my modded Alesis Bitrman, when I have a sequencer together, to get sequenced ring mod, frequency shifting, bit crushing, aliasing.  Should be pretty stupid.

  Of course making everything voltage controlable would be more of a project than each effect would be, probably, and feature creep would be likely to sink a project like this, also the inevitable desire to be able to go between a couple different configurations on the fly for performing could get absurdly complex.  If you were selective with which features got shared between modules, though, it could be very cool.  RG wrote this article on having a sort of floor "rack" where you can stick modules of a couple different sizes. 

For the spaghetti factor, the thing to do is decide what the most common configuration would be, and have that hardwired using normalled jacks, so you can get your alternate crazy sounds with the rats nest of cords.  I do think that having a bunch of jacks and cords is better than elaborate internal switching schemes, as far as a mortal diyer being able to get something finished and working.  Maybe little trim knobs by each jack to trim the control voltages down to what the effect wants to see.

What would be a good standard for stompbox control voltages? 0v-5v? I bet Paul Perry has some thoughts if he sees this.

[j.frad]

I'l planning to build something like that, using one Vanishing point-type circuit and an LFO to control one of tim escobedo's idiot wahs and the frequency control of the "doctor who thing modulator" .

The idea is to have everything in one box with a common power supply plus a blender module and to use external jacks to connect the audio to the filter or modulator and other jacks to connect the controlling modules to the controlled ones.

I haven't planned anything to normalise the control voltages though, I'll just try to adjust values until it works like I want it to.

[object88]

What would be a good standard for stompbox control voltages? 0v-5v?

0-5V is (the?) common control-voltage range for modular synths.  If you stick with this, perhaps you could score some utilitarian modular synth PCBs and save yourself a little footwork (and get to concentrate on the "exciting" bits).  For example, here, and (soon) here.  Note, however, that many modular synths expect +12V or +15V power, sometimes with negative rails too boot, so you might need a little extra planning.

[Floyd Pepper]

In case anyone's interested in modular synths:

Here's someone else selling modular synth PCBs http://www.musicfromouterspace.com/
Here's an interface for guitars into synth modules http://www.cgs.synth.net/modules/cgs46_sba.html
And trigger your modular's gate with this http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/guitar_trigger.html

Colin at Experimentalists Anonymous has shown you can build a modular synth in a month http://experimentalistsanonymous.com/other/siam/

The demo of Nord's Modular is cool - build a modular synth on your PC - http://www.clavia.se/products/nordmodular/demo.htm

[Processaurus]

The CGS stuff looks good, I've been meaning to get Ken Stone's waveshaper module and stompbox adapter (to stompbox-ize his modules) to use with guitar, on the page he himself suggests it would make a "novel" guitar effect.  The stompbox adapter looks nice, has the +/- 15v supply and a relay for a remote bypass.

Wonder how a big muff with a moog ladder filter instead of the tonestack would sound?  Moog Muff?

[slacker]

Yeah the CGS modules are cool. The waveshaper can probably be converted to run on 9volts so you wouldn't need to mess about with the whole +-15volt business. My slackfilter is based on a couple of Ken's circuits and works very nicely on 9 volts.
Gettign the post back on topic I've been thinking of adding expression in and out jacks so you could use the LFO/envelope follower with other pedals. I reckon you could get some pretty cool sounds running multiple effects off one LFO.