Muff's Modules & More

[negativspace]

So... I've recently been tasked with building a couple of these for some fellow wigglers. The CVP is easy - I've built like 200 of them before - but it's designed for Euro and some of its features just don't make a lot of sense in the Buchla thanks to banana jacks. (Buffered multiple jack, 2 outputs?) So it seems like some modification is in order. First, one needs to mix the two inputs per channel. Second, the lower output per channel should really be inverted relative to the top output. All of this requires active circuitry, and that brings us to the point of this thread - I'm going to make a PCB to handle all of that.

The functions onboard are simple: 4 2-input mixers and 4 inverters. This will let you seamlessly complete the Buchla panel build as described above, but with some normalled jacks, pots and switches one can construct any number of useful utility modules in a standalone situation.

The circuitry is also simple - 3 TL074s and some resistors are all that we'll need. So the PCB is just about exactly the same size as the CVPs. The power footprint is the same too, either to facilitate bussing with the Buchla panel or to facilitate use in a standalone situation.

Here's my first stab at the layout... I need to doublecheck the inverters and reroute the power traces through the capacitors by the beads, but otherwise I think it's good.

[negativspace]

The boards have been ordered. I expect delivery sometime around 12/20 and will probably ship immediately after the Christmas postal break.

The PCBs are silk-screened and masked, and will be $18/ea. Shipping is $3 domestically or $5 internationally. The PayPal address for payment is jcoates42@gmail.com.

Order List (blue indicates paid, red indicates shipped)

negativspace [4]
303monkey [2]
RSFC [2]
pfurmel [1]
Junk Rhythm [2]
jooks [1]
fluxmonkey [1]
djs [1]
Votek_Mendo [1]
keninverse [1-2]
janvanvolt [2]
bsmith [1]
xerxl [2]
msprigings [1]
frozenkore [1]
djangosfire [2]
monokinetic [1]
rosch [2]
valis [1]
wavehead [1]
mattrick [2]
nangu [3]

[303monkey]

I would be up for two!!

[Rod Serling Fan Club]

I need 1 or 2. If you have room, a dc mixer might be nice. I was planning on using the right bottom jacks as mixed output, just using a different color nanner jack differentiate from the "format jumbling" jacks.

[negativspace]

I'll see what I can do... another dual opamp shouldn't be too hard to squeeze in there. My initial idea is to keep the power connector in the same place so you can bus all 5 boards together, but if I have to widen it a bit to accommodate all of the ICs then so be it. Function over form. (Well, at least behind the panel!)

[negativspace]

You know, now that I think about it, why don't I just use standoffs and mount it to the bottom CVP board? Ha, ok, this just got even easier.

[Pfurmel]

I'm in for 1 fo sho

[Junk Rhythm]

I'll take 2.

[valis]

Would you need one daughterboard per Buchla-ish panel or one per CVP PCB?

[jooks]

Wow! Im in for one!

[diophantine]

Doh! 24 hours after I finished building mine. I left mine w/the buffered copy of the input, and multed outputs - figured it would make it simpler for chaining some of these together.

[negativspace]

[janvanvolt]

are those for eurorack or buchla ? if they are for eurorack i'll take two.

[negativspace]

They're for Buchla, but I suppose you could build one in Euro as a standalone if you need inverters and mixers.

[fluxmonkey]

i'd like one, please & thankyou!

[negativspace]

I've updated the first post with an image of the PCB.

[valis]

[PF]

Im in Jason ....,

[djs]

i'll take one

is the invertor between +v and zero, or inverts to -v?

[Votek_Mendo]

One for me please, Thanks!