Modular approach to all the effects!

[Matthew Sanford]

Hi All!

So, circuits are a bit modular anyway, right? Lot's of blocks in them doing their separate jobs, etc.
I've finally dove into it all the tail end of last year, starting by building a Distortion+ clone for a kid (poor kid!) and working a PT2399/STOMPFLO/Ring Mod circuit...well, I gotta get more done with the RM, which is more AM now (maybe breakdown and get the audio transformers instead of resister mock up...or look at the 111 RM using transistors), and the circuit was really just a PT Wobble or Fideleater pale comparison (oh I love that fideleater!). I did order and plan to try the One Shot instead of the STOMPFLO - figure the oddities can be added when wanted that way, so I'll get there...

But, it got me thinking as I look upon the myriad of circuit blocks laid out on small breadboards, why not go modular? I mean it is currently, and who knows if I will want the STOMPFLO, or ONE SHOT, or an envelope by my playing dynamics to make the PT weird? What if I want to through the STOMPFLO as Vref for a TL071 distortion to get tremolo-ey with it? So many possibilities...

So my question: What  ways are there to go modular? I have been playing with using a single gang steel electrical box to put each in, maybe a pop out on the back to put it on a pedal rack with a plug for all the buses connecting there, but it seems a bit big for small circuits. Was thinking I should look into the Eurorack bus setup, but then thinking, say STOMPFLO set per Tom's schematic in a small tin,  pair of sockets wired for the LFO, options post passive & active filters as well, then another for tap tempo, then sets of 3 for the Offset, Freq, Wave, Depth controls. From there, smaller tins set for momentary switch, pots, stereo 1/4" jacks (to send to expression pedals), etc. with a vactrol driver as well, perhaps being a connector that can accept jumper cables or a male connector to just plug the control (pot, switch, etc.). Is this madness? I just envision it more like a synth, where a pedal board just has options to mess with different things in different ways at the drop of a hat (or replugging of a cord). Was thinking power buses on the board for 9v and 5v and 0v, then maybe 4 audio buses so that put to an effect could select for in/out being 4/3, or 3/2, or 2/1 (working on screwing a strat that way, switches so they can feed each other whichever way or all in a line, or some off).

So, lots of different sized tins stacking on or next to each other for different drivers, effects, controls, etc... is this madness? Any ideas on the interconnection parts (direct to each other or all plugging through a board), housing, etc.? Basically trying to keep the changeability of breadboards (without switching component values) into the final thing...

Actually, has anyone done this? Set up an effect with different earlier signal blocks to choose from without it being all in one with switches for elements?

[Mark Hammer]

Apologies upfront to all those who have seen and heard this all before.  But, Matthew is relatively new here, so here goes...

A little over 15 years ago, a surplus place near me was selling some sweet little 4" x 2.5" black anodized aluminum faceplates, with predrilled holes in the corner, for either 3 or 4 for a dollar.  I scooped up about 30, figuring I'd do something with them later on.

"Later on" came, and I realized I could make "pedals" for peanuts by using the faceplates to go modular.  I built some cabinets, each capable of holding 12 modules.  Because it was for ME and not for selling, I could use whatever I wanted.  And I decided to use 1/8" in/out jacks, and DPDT toggles for bypass.   (Compare that cost to 1/4" jacks and 3PDT stompswitches.)  And because I wouldn't have to worry about spacing a stompswitch where I wouldn't accidentally step on pots of toggles, I could stuff a LOT into that 4 x 2.5" format.  Power is provided by running cables to a bus, using Molex connectors. 

I'm finishing up cabinet #7, and slowly getting #8 ready.  One of the cabinets has its own bipolar supply for circuits that need that, and the others are +9V-only.  I lucked into a nice little MXR power brick on a local 2nd hand site, that provides 8 outputs at up to 500ma each, so I run cables from it to the seven cab using +9v.  Happily, since it is pretty much all analog, the current draw for any cabinet isn't too high.  I ran out of anodized faceplates a while ago, so I ended up using aluminum sheets I bought from a hobby store, and eventually some aluminum siding contractors left behind, from a job they did for our house.  I just cut the pieces to size, spray them black and drill appropriately.  Starting to run out of needed letters from my stash of white rub-on lettering, so I have to turn to superfine paint pens.  And many circuits that used to be in boxes have been slowly migrated over to modular format.

The nice thing is that this approach is so economical that I'm happy to make "throwaway" modules for things I wouldn't want to spent bigger bucks on.  That also includes "utility" modules, like the pair of splitter/mixer modules I made for running things in parallel, and a module with tunable lowpass and highpass filters.  Gotta curtail my enthusiasm, though.  I was cataloging stuff and realized I had made duplicates of a few things!

[Matthew Sanford]

Thank you Mark, that is sort of what I was thinking and realize a modular approach is very well older than DIY pedals - after all in Anderson's book (hope I'm not mixing up names, ...projects for musicians...) much is presented to be in a cabinet.

I really appreciate the story and may track down threads. I've been a voyeur here for a decade, now and again, but only recently knocked on the door.

For me it's always about economical approach and up cycling. I was thinking less a cabinet and more little boxes to snap together, but the essence is the same. I think I will still work on it, if only to create circuits on Vero with sockets marked well as desk tools to free breadboards so they can jumper in to different places...to streamline the limited time and my scattered direction with it (must learn it all at once, and why don't I already know these things?!)

In the meantime learn how momentary switch's make FETs change clean to effect and a million more questions that need their own posts (or better, thorough searches here prior to posting!)

Thank you for taking the time to teach, and I apologize for any annoyance the repeats may cause

[Mark Hammer]

Look into relay-switching.  Better than FETs.  And if you have the space, and external power, why not?
One of the things I like about the cabinet approach is the much greater depth afforded. No worries about things shorting out against enclosure walls either.

[ThePracticalPeasant]

Look into relay-switching.  Better than FETs.  And if you have the space, and external power, why not?

Once you're using relays like this, drive them with Arduinos and use those little 2x16 I2C displays to show, for example, which of your bank of fuzz effects is active. I doubt you'd want to bring such devices into the actual signal chain, but using them to manage the bypassing might be useful...

... just a thought.

[Mark Hammer]

One of the nice/handy things about nonlatching relays is that they can easily be used in latching OR nonlatching/momentary mode, simply by the footswitch one uses.

[juancra]

Apologies upfront to all those who have seen and heard this all before.  But, Matthew is relatively new here, so here goes...

A little over 15 years ago, a surplus place near me was selling some sweet little 4" x 2.5" black anodized aluminum faceplates, with predrilled holes in the corner, for either 3 or 4 for a dollar.  I scooped up about 30, figuring I'd do something with them later on.

"Later on" came, and I realized I could make "pedals" for peanuts by using the faceplates to go modular.  I built some cabinets, each capable of holding 12 modules.  Because it was for ME and not for selling, I could use whatever I wanted.  And I decided to use 1/8" in/out jacks, and DPDT toggles for bypass.   (Compare that cost to 1/4" jacks and 3PDT stompswitches.)  And because I wouldn't have to worry about spacing a stompswitch where I wouldn't accidentally step on pots of toggles, I could stuff a LOT into that 4 x 2.5" format.  Power is provided by running cables to a bus, using Molex connectors. 

I'm finishing up cabinet #7, and slowly getting #8 ready.  One of the cabinets has its own bipolar supply for circuits that need that, and the others are +9V-only.  I lucked into a nice little MXR power brick on a local 2nd hand site, that provides 8 outputs at up to 500ma each, so I run cables from it to the seven cab using +9v.  Happily, since it is pretty much all analog, the current draw for any cabinet isn't too high.  I ran out of anodized faceplates a while ago, so I ended up using aluminum sheets I bought from a hobby store, and eventually some aluminum siding contractors left behind, from a job they did for our house.  I just cut the pieces to size, spray them black and drill appropriately.  Starting to run out of needed letters from my stash of white rub-on lettering, so I have to turn to superfine paint pens.  And many circuits that used to be in boxes have been slowly migrated over to modular format.

The nice thing is that this approach is so economical that I'm happy to make "throwaway" modules for things I wouldn't want to spent bigger bucks on.  That also includes "utility" modules, like the pair of splitter/mixer modules I made for running things in parallel, and a module with tunable lowpass and highpass filters.  Gotta curtail my enthusiasm, though.  I was cataloging stuff and realized I had made duplicates of a few things!

Hi Mark, I've got a question on this: Is this kind of approach as noiseless as having every effect in his own housing? As I'm also doing things for myself I would love to build something similar.

Thanks, 
Sebas.

[frequencycentral]

These look great Mark! You're a trailblazer:-)

[Mark Hammer]

I don't see the risk of noise as much greater.  The in/out wires are every bit as short.  With the modules being the same size, and relocatable, you can always configure them for the shortest patch cable run.  Although each module is not "sealed" in its own enclosure for shielding, one can always line the cabinet with shielding material, and can always use shielded cable, where you feel it necessary.

As for being a "trailblazer", it's just my general cheapness.  Much of what I did has already been done by other companies, which faltered when they couldn't provide the range of effects themselves, and couldn't get buy-in from other makers on a standard, to sustain the idea and marketability.  The thing that made it feasible for me was the availability of resources that permitted me to populate it with pretty much everything I might want or need - something that previous commercial attempts never achieved, or could.

[soggybag]

You might as well get something like this: https://www.befaco.org/i4-instrument-interface/ it's an instrument interface, I built it from a kit. Then you could just use all your eurorack modules as signal processors, totally modular!

I few companies make pedal interfaces for eurorack. You can add on of these to your system and be able to plug your favorite pedals in series with your favorite module gear! https://rmlfx.com/archives/1479