A no-input-mixing approach in Eurorack?

Sorry if this sounds newbie-ish, but I was wondering if the idea of no input mixing can be exported in Eurorack. Something like having a matrix mixer patched into itself, or just a chain of several VCAs going into each other, or some multiples passing feedback loops between themselves. I love the idea of no input mixing, I'm imagining what sort of coolness would arise by CVing it with control modules or other stuff.
I have a Veils, a Bastl ABC and a Gargoyle Delay and I get some squarewave-like feedback tones if I cross-patch those two, but maybe there are some other modules which have more ground hum that could serve a feedback-oriented approach. Maybe DYIing them would be the answer? Or maybe this just isn't the format for this kind of explorations and I just should go with a regular no input mixer (which would sadden me, alas). If anyone has more information it would be lovely to expand on this idea.

What about the Bastl Dark Matter? If I remember correctly, that’s sort of the heart of that module but I haven’t looked into it too much.

I've read about the no-input approach a while ago but never tried it. But if you searching for Modules who are producing a lot of noise, then take a look at the endorphine Milky Way and the Squawk Dirty. They are notorious for being noisy.

To farkas point. The Bastl Dark Matter does weird stuff and creates feedback loops, but i think it needs an audio source. I guess that is not what you want to do.

One Module who could be interesting is the Instruo Lion.

the instruo lion is a very expensive version of a matrix mixer - there are others that will do the same (less the pegs - that in my case I would loose) for less money - Doepfer do a good one (one of the most ergonomic) and so do AISynthesis

whenever someone recommends a shiny new expensive module - remember to look around and see what else there is that will do the same thing (or almost the same thing) for less money!

whenever someone recommends a shiny new expensive module - remember to look around and see what else there is that will do the same thing (or almost the same thing) for less money!
-- JimHowell1970

Sure, you might be right with that, but there is a huge difference between the lion and the doepfer 138m. The lion isn't more expensive without a reason. And for his use case the lion is suitable. The doepfer is not (or almost not).

whenever someone recommends a shiny new expensive module - remember to look around and see what else there is that will do the same thing (or almost the same thing) for less money!
-- JimHowell1970

Sure, you might be right with that, but there is a huge difference between the lion and the doepfer 138m. The lion isn't more expensive without a reason. And for his use case the lion is suitable. The doepfer is not (or almost not).

-- MillionJT

@MillionJT - you may be right - I'm just a little skeptical - so I took a look at the spec for the lion (just the description here) and apart from the 'expensive pin matrix' (which is one of the 2 obvious reasons why lion is more expensive, the other being that it's built in Scotland and not China) and the black panel - I really don't see a lot of difference between the 2 - they're both matrix mixers at the end of the day...

it could be that the lion can add a lot of gain, but I don't see that in the specs - and if that's the case you could easily patch say +20db of gain in via Veils or something

so could you please explain why the lion is more suitable as a matrix mixer than the doepfer for no input mixing? or is it just differently suitable (ie the lion has this extra function that you would need another module for)

This actually makes quite a bit of sense, and I'm a little surprised that no one's tinkered with no-input feedback paths all that much in Eurorack.

If you go back to one of the pioneers in this, namely David Lee Myers (ie: Arcane Device), his systems were largely built around matrix mixers tandemmed with delay lines and some other filters and timbral modifiers. This should be VERY easy to implement in Eurorack. Add some modulation, a bit of the typical Eurorack voodoo, stick it all in a Behringer cab, and I came up with:

Pretty cool...the left end is the modulation section, uses a Maths, Quadrax and eight free-run LFOs, plus a few mixing/modification modules to make that do a ton of interactive crossmodulation, plus output some VERY wild curves. You get six VCAs (switchable curve) after that for modulation and audio amplitude control as needed. The "beefy" part is in the center, where you'll find an 8 x 4 matrix mixer plus a pair of Pittsburgh Delay Networks, and there's also a touchpad-controlled switch for either audio or modulation. The right end (audio processing/output) contains eight VCFs, a really useful output processor (the T-racks...I have the standalone version, and it's VERY feedback-friendly), plus your submix from the four outputs of the matrix (you'd split these...and for that, I also added four buffered mults to make sure the audio levels stay up when splitting, if necessary). Then there's an Isolator for your isolated stereo outs plus your master output level.

Now that's a nice start-point...or if you like, a finished solution.

EDITED Mar 16th 2021, 04:14

Thanks everyone for the detailed answers.
This system is very interesting! Since I already have a somewhat developed "sampling" section (W/, Nebulae and other stuff) I think it will be very cool to integrate it with something similar to what you describe, Lugia.

As for the matrix mixers, I'd be genuinely curious to know exactly what the 138n cannot do that the lion can. The price gap is quite wide, so I'll take some time to decide. DivKid's video is very comprehensive, but I also found a lesser known video of someone playing with a 138n and feedback. (What would happen if I played them with Landscape AllFlesh cables? That would probably be quite something.)

If you go back to one of the pioneers in this, namely David Lee Myers (ie: Arcane Device), his systems were largely built around matrix mixers tandemmed with delay lines and some other filters and timbral modifiers. This should be VERY easy to implement in Eurorack.

I actually didn't know Arcane Device. Listening now. WOW...

so could you please explain why the lion is more suitable as a matrix mixer than the doepfer for no input mixing? or is it just differently suitable (ie the lion has this extra function that you would need another module for)

-- JimHowell1970

As for the matrix mixers, I'd be genuinely curious to know exactly what the 138n cannot do that the lion can. The price gap is quite wide, so I'll take some time to decide. DivKid's video is very comprehensive, but I also found a lesser known video of someone playing with a 138n and feedback. (What would happen if I played them with Landscape AllFlesh cables? That would probably be quite something.)
-- gio_coder

I think the pin-matrix is a major difference, since every patch point is a combined send and return. Imho there are plenty of ways how you can crosspatch and create Feedback loops with the lion. But to JimHowell's point, that might not be a big enough advantage.

p.s. @gio_coder I guess you meant the 138m not 138n.

I think the pin-matrix is a major difference, since every patch point is a combined send and return. Imho there are plenty of ways how you can crosspatch and create Feedback loops with the lion. But to JimHowell's point, that might not be a big enough advantage.

p.s. @gio_coder I guess you meant the 138m not 138n.

Yeah, it's probably the pin matrix. I still need to wrap my head around that. I meant the 138m, sorry for the typo. Thanks again!

I think I have to go and watch a video on the Lion to check it out further...

I hope instruo sell replacement cables for the pin matrix - if I bought one I'm sure I'd loose them!

well I went and watched the divkid video and then his chat with Jason from Instruo

interesting module - not for me - as I said I'd loose the loop cables or have them in a pencil case where I forget I have them - I have some plankton ninja stars and this is what happened to them, because I could never find them!

I didn't see no-input mixing as an example in the video, so I'm off to youtube to search...

I think if this was something that I was going to try I'd try with a simpler matrix mixer to start with - but then I already have a couple!

I didn't find any lion no input mixing videos - but I did watch a tutorial on no input mixing by Sarah Belle Reid... so not all lost

lion certainly looks like a fantastic module - I really like the patch programmability aspect of it - maybe I'll pick one up sometime in the future if I see a used one for a decent price