First small rack for guitar and other audio processing

Hi, I have a 3U, space left in my table and thought I would use it for a small audio-processing euro-rack, based on the 84HP Behringer Euro-rack Rack.
This would be my first euro-rack build and I would appreciate any comments.
The rack would primary be used for processing electric guitar/bass and harmonica. I have lots of pedals, so I like this to have a "far out/weird" sound of its own.

What elevates Eurorack effects modules from guitar pedals is the ability have voltage control over many of the parameters, either through hands-on manipulation or by utilizing control voltage generators like LFOs, Sample&Hold, Sequencers etc.
You have Pams New Workout in thhis setup, which can provide up to 8 CV sources, but lacks immediate control due to only having one encoder. But even if you use all of Pams outputs, you still have vastly more CV inputs on your three effects modules that you aren't using. I would drop at least one, if not two of the effects modules and add more CV sources, mixers, maybe a filter and, most importantly, VCAs into this system. One knob per function-type modules will make your effects rack very playable. Also think about mixing several modulation sources together before sending them to the CV input of one of the effects. This is almost mandatory if you want to go beyond what you can do with guitar pedals anyway.

Hello,
I have a same question about the very same topic.
I'm new to modular and started to get interested into this since few weeks, but have years of experience with guitars, pedals, synth, noise machines, etc.

My possible approach to a modular system would be to have something that I can both use stand alone (like in a drone/noise/ambient manner) or together with my guitar and synths and made so that I can implement/interface it also with instruments levels so that I can rout it thru my guitar pedalboard for example.

I did some experiments with VCV Rack, and found very powerful a combination of Plaits and a second VCO/oscillator combined with a quad LFO to generate sounds and drones.
After talking with a friend and try out few his modules, I also got very interested about Schlappi and Noise Engineering modules. For example I like a lot the Desmodus series, since the same module can be loaded with all firmwares available. Boundary looks like I swiss army knife that I can use as VCO, envelope, etc...
But I also find Doepfer modules to be super cool, simple and utile to what you need them for.

I would like to keep it as small and compact as possible, like 64HP. After few mindstorms, I came up with this first idea, pictured below.

My only concern at the moment is the Strymon AA.1: are there any other alternatives out there for such "guitar interfaces", so that, as said, I can insert my guitar (or another synth) into this system and then go out back into my pedalboard?
What modules to you use? Otherwise any other advices?

EDITED Aug 9th 2022, 16:53

Well, I didn't get this to fit in 64 hp...but you might want to have a look anyway...

Bigger makes this work. Here's what's there...

First up, I went with an Intellijel Palette 104 so as to keep this build gig-bag-able. This also gives you a set of buffered mults and some adders, along with the four 1/4" I/O jacks, and it contains your power supply. The buffered mults in this case can be used to mult-out a stereo pair to three outputs (using two mults, natch), leaving a third for modulation routing.

The tile row here is pretty significant as well. Your stereo inputs are on the left (fed by a pair of the 1/4" jacks), then a QuadrATT lets you mix modulation, or you can use it as a mono mixer...or both, since you can "break" the output bus into a pair of two-channel outs. This also gives you the ability to attenuvert various modulation sends, it functions as a DC offset source...very useful thing. Next, you'll note the VCO right next to a ring mod tile; the VCO is the ring mod's "carrier", offering four waveforms. Plus, that VCO can be dropped into low frequency rates...so, send a slow square wave in one side, the guitar in the other, and voila! Instant "Crimson and Clover" audio chopping! After those are two more utility LFOs...both of which have wave restarts, which is also important here (you'll see why in a bit). Then the output mixer lets you separate two different mixes and then combine them when going into the outputs (the other two 1/4" jacks). This should function as a very capable wet/dry control...run your dry signal (or maybe the wavefolder output?) into pair #1, your FX mix into pair #2, adjust as desired.

The MODULE row, though...that's where things get interesting!

First up is a pair of ADDAC 301 pedal interfaces. These have an expression pedal input as well as a "latch" switch for sustain...or for firing something else, such as the huge thing at the end of the row. After that, a Bastl Dynamo does double duty by providing two channels of envelope following/gates, plus an A-B switch, all under the control of the input signal's dynamics. After that, there's a trio of AR envelopes from Nonlinearcircuits and a rather twisted LFO from Erica. The Black Octasource is a single LFO...but with eight outputs, all set 45 degrees of phase from each other. With that, you can have things like autopanning, weird modulation "lumps", odd modulation "cancellations", etc. Sure, you could have four LFOs...but this thing gives you eight ways to use one LFO, all in perfect sync. The Black Noise Voltage Processor is your waveshaper...stereo waveshaper, in fact. Get used to that word, btw...from here on, the entire audio path is STEREO.

So, once you get past the waveshaper, you're into the effects. The first two are from Xaoc...their 4-pole multimode stereo VCF, followed by their CV controlled frequency shifter (also stereo). You might notice the lack of phase shifters or flangers here, and that frequency shifter is the reason. It can do those things, but it can do them to extremes; crank the shift control, and everything turns into clangers and howlers with gnarly anharmonic timbres. But turn it back down to just barely off zero, and suddenly you've got this phasing...SOUND. Nothing like 'em, really!

Then we've got an Alright Chronoblob2. This stereo delay hides a surprise: an insert in its regen path. Want to listen to things warp out of shape with each repeat? Insert the frequency shifter into the Chronoblob's regen, set the shift for a half-step, and hear the echoes whirl upward into weird aliasing. Or drop the VCF in, and degenerate the repeats, or or or... Anyway, after that is Mutable's Beads...which, if you're going to get one, you'd better hurry as Emilie is shutting down pretty much now. But if not, no prob...there's 14 hp variations on the very similar Clouds that'll drop right in if you don't get lucky.

And then, the Qu-bit Synapse. This is billed as a "crossfading switch", and it's a bit complex as to what it's capable of. But one thing that immediately comes to mind here is the fact that the Synapse can store and recall eight different settings, and you can access that via its "advance" jack. That's why the ADDACs with their footswitch capability is there, as one of those footswitches can be dedicated to that "advance" control. Otherwise, it's sort of like a variation on Mutable's Frames mix-scene module...set up your signal path, CV levels, etc etc, and store it.

So, no...I totally blew it on the form factor. But that was very deliberate on my part, because that 64 hp build was very restrictive due solely to the available space. By shifting to a Palette 104, though, I was able to toss a LOT of potential into the build...and in the end, 104 hp isn't that difficult to shlep around, especially if you pick up one of these from Intellijel: https://intellijel.com/shop/cases/gig-bag-for-4u-palette-cases/ Not too shabby, those...about the size of a violin case, actually.

EDITED Aug 10th 2022, 03:19

Hello,
I have a same question about the very same topic.
I'm new to modular and started to get interested into this since few weeks, but have years of experience with guitars, pedals, synth, noise machines, etc.

My possible approach to a modular system would be to have something that I can both use stand alone (like in a drone/noise/ambient manner) or together with my guitar and synths and made so that I can implement/interface it also with instruments levels so that I can rout it thru my guitar pedalboard for example.

I did some experiments with VCV Rack, and found very powerful a combination of Plaits and a second VCO/oscillator combined with a quad LFO to generate sounds and drones.
After talking with a friend and try out few his modules, I also got very interested about Schlappi and Noise Engineering modules. For example I like a lot the Desmodus series, since the same module can be loaded with all firmwares available. Boundary looks like I swiss army knife that I can use as VCO, envelope, etc...
But I also find Doepfer modules to be super cool, simple and utile to what you need them for.

I would like to keep it as small and compact as possible, like 64HP. After few mindstorms, I came up with this first idea, pictured below.

My only concern at the moment is the Strymon AA.1: are there any other alternatives out there for such "guitar interfaces", so that, as said, I can insert my guitar (or another synth) into this system and then go out back into my pedalboard?
What modules to you use? Otherwise any other advices?

-- gila_crisis

Hi, have a look at the Bored brain injectr. It has a guitar preamp, envelop follower and Fx-loop for pedals.