4x4 passive matrix mixer

[Glace_Noire]

I plan to build a 4x4 passive matrix mixer, but I failed to find a proper schematic on the internet since everyone seems to use different pots or resistors value
Is anyone here who already did something similar?
Is the guitar signal will be divide between each output and so it will lose some gain to "attack" the pedalboard and/or the amp according to my plan?

[crochambeau]

I think you'll want a more or less standard level at the inputs, based on my (potentially errant) guess that your contact mic and guitar are plugging direct, you're going to essentially lose them in the face of the Volca and pedal board.

I'm awash in deja vu right now though, maybe I need to access the thread somewhere that reminds me of this, and get firmer footing.

[Glace_Noire]

Thanks for your help dude!
You're right: I plan to plug my guitar and contact mic direct in the mixer.
And so I roll back the volca and pedalboard feedback loop pots, do you think I could have an acceptable balance between output levels?

[crochambeau]

You could balance it, but I would expect you'll be ahead if you put a boost/buffer on those two. In my experience, highly disparate signal types don't lend themselves well to passive combination, though to be fair I haven't climbed aboard the matrix mixer train. Upside is: you can simply build the matrix mixer and add those parts externally if needed.

Regarding actual schematic, often times the end value is not critical, or benefits from being scaled up or down depending on how many channels you're building and the type of signal you expect to see at input.

Given a four channel, you're going to have four of the pots IN PARALLEL loading down each input, so... if you grab a 100K pot the branch load at input will be 25K. Most everything active will be happy with this value, your guitar might shit out a lot of the top end (solved via a buffer, so let's pretend that's not a huge concern) and I tend to gravitate toward 10K as a mix buss resistor, though you'll get a fair amount of crosstalk with hot signals.

In my mind, that covers it, though if you have anything +/- 50% in value you'll have similar results would be my guess.

I can dig up a drawing if there's confusion still afoot...

[karmablock]

This is for a 6x6 just don't use the last two.

[Glace_Noire]

After spending the last two months on a job change and a move to a bigger city, I'm finally able to begin my matrix mixer project

[Nocentelli]

Excellent, saw cloudscape's excellent 4x4 build recently and thought I might try building one.

[spacelordmother]

Very interested to see/hear how it turned out!

[Glace_Noire]

Just finished it yesterday: it works like a charm, first time!
Wiring started super clean and then things gone wild

[spacelordmother]

Looks awesome! Did you just follow the schematic above? Did you add the boost or buffer?