3x3 Matrix Mixer Project

Would anyone be interested in this project?
For some reason I’m really into mixers lately.

3x3 layout … it will be a large project if I decide to do this. 5x LM6172
and I have 1 stage left, maybe an inverted input but that would mean 3 more pots. and there are already 12 :upside_down_face:


  • feedback routing
  • color mixing.

features: (for now)

  • 3x input with 3x pots per channel - so 9 pots
  • 3x output with 1x gain pot per channel

Things that might change:

  • gain pots: they can be in the feedback loop ? for better amplification / soft keying?
  • inverted inputs without pots. IDK if that is useful, but it would save panel space
  • SMD? maybe?

I’m open for idea’s!


well I was just thinking about buying a doepfer matrix mixer - as there were no diy ones I could find that I liked

so why not

conditional add to group buy - if you do this I need 5 more


Yep definitely interested in this!

Schematic looks OK – but make sure you ground the noninverting input on the unused opamp, and connect a 1K resistor from inverting node to output. That way you won’t get any potential ringing or oscillation from the floating terminals.


I might want to use that last opamp for something more useful, that is why it is still floating :slight_smile:
Maybe I’ll add a inverted input, or at least a mod input for expansion possibilities. to keep the DIY blood flowing!

1 Like

I can definitely see me wanting at least one of these please yes

Also Interested! Nice work @reverselandfill


These modules are not the most exiting things you could think up (as opposed to filters, effects and oscillators) but it is where I am right now in my personal electronics development. I’m mostly building on opensource schematics by LZX and others, adding some features I think might be useful. The help from @creatorlars is invaluable!

And I do think it is cool to have more DIY video projects in the ever expanding universe of modular !


Hey, what’s up? I have been working on something like this too. I was doing a 4x3 matrix. I just got access to a desktop milling machine, so I was going to prototype it.

I have another surface mount variation using a max4392. I’m willing to distribute whatever and collab if anyone is interested!


As mentioned in the previous 2x2 mixer thread, I am now finding that yes…buffers are our friends. Rev 2 Doh!

this sounds useful and great!

if I can get one built then I’d be in!