Eurorack integration for lazy people ! ; )

modular
#1

Hi!

I want to interface my Axoloti with my eurorack, but I don't have electronics knowledge for make an op-amp scaling.

The idea is to buy a couple of utility modules from Doepfer.

One is for scaling the 3.3 v analog out, to something more suitable for eurorack (5v), for send gates :

http://www.schneidersladen.de/en/doepfer-a-183-3-dc-coupled-amplifier.html

And another little utility module for make the audio out of axoloti to work at modular levels:

http://www.schneidersladen.de/en/doepfer-a-119-external-input.html

The idea is to use axoloti as a midi controlled oscillator, this oscillator audio goes to my eurorack, for being filtered, and the gate out is for trigger the amp and filter envelopes of my eurorack
What do you think ?

Cheers

#2

Or maybe I can just the digital out, since gate in eurorack it's just an on off signal ?

#3

You'll need to do level conversion somehow. A digital out on Axoloti is also 3.3V when on.

#4

Yeah, I know. this is the reason why I adding this module, for amplify the 3.3v signal to 5v :

http://www.schneidersladen.de/en/doepfer-a-183-3-dc-coupled-amplifier.html

#5

You could also use a comparator to trigger when it crosses 3V or so. They might be cheaper.

#6

Cool idea!

Something like this?
https://www.modulargrid.net/e/circuit-abbey-tripfire

So, if the signal from axoloti compares to the reference voltage, and it's higher voltage, it produces a gate? So I guess if in the voltage reference nothing it's plugged, the aoloti voltage will be the one who rules (3.3 v vs 0v reference), and will fire a gate.

I'm correct ?

#7

Correct. You can usually set.the comparison threshold voltage by a knob or sometimes by CV. When the axo goes above the threshold it will.fire a gate.

#8

To one you linked only has one comparator and a gate delay- if you want to send multiple gates from axo there ate some other modules with multiple comparators and no delay. See here: https://www.modulargrid.net/e/modules/browser?SearchName=&SearchVendor=&SearchFunction=56&SearchSecondaryfunction=&SearchTe=&SearchTemethod=max&SearchBuildtype=b&SearchLifecycle=&SearchSet=&SearchMarketplace=&SearchIsmodeled=0&SearchShowothers=1&SearchShow1u=0&order=newest&direction=asc

#9

Thanks for the suggestions !

I found this:

http://www.schneidersladen.de/en/cg-products-add1.html

2 comparator circuits for 55 e.
(it can be use as an adder to, so good bang for the buck)

#10

And now i'm dreaming of a compact hybrid analog/digital paraphonic semi-modular synth for lazy me.
Complex osc with the axoloti, tube amplifier, analog filter and a spring reverb in a mini case :yum:

#11

Dreaming? Just do it!! I'll love to see it !

Cheers !

#12

Haha ! The more i think about it, the more it looks complicated for lazy me.

I'm picturing a bi timbral or bi osc sound generation patch on the axoloti for the left and right output.

Two tube amplifier is a lot of space & money :disappointed_relieved: There is cheaper tube amplifier but with the tube inside (probably the same sound but... :wink: ). i'm pretty sure it need an uncommon or extra power supply. Metasonix has a noisy reputation. Erica fusion mixer looks good but a bit overpowered for this idea. Elby design seems a good idea if i swallow the dream of having two glowing lamps on a synth.
However, if i forget totally the tube fetishism, the doepfer amplifier seems pretty good or the future InAMP from Befaco .

Doepfer mini case only provides slots for 4 modules i see. seems tight for the amplifier, comparator, filter (oh god which one ?), dual function generator (one used for volume env and the other for lfo/osc/env), spring reverb, mixer/multiple and 6.5mm jack output.
Also i need to think about how i can manage keytracking on the filter and not losing my girlfriend if she finds an invoice for modules.

But that's some foods for thought !

Cheers !

#13

The simplest way to control the Axoloti from your modular is with a CV to MIDI CC module like the ADDAC221 or the Doepfer A-192-1 or ones like them. These modules convert the CV voltages into MIDI Continuous Control commands which you can assign to knobs and such on the Axoloti. There are also some DIY type PCBs from Doepfer that will work for this like the Pocket Electronics (pots, switches, CV to MIDI CC) and the MTC64 MIDI to Contact/Gate controller boards which would interface with the least amount of extra circuits needed. The MTC64 converts up to 64 succeeding MIDI note on/off or program change messages into 64 TTL voltages (0/+5V)