Universal Buffer - Single Input w/ Volume Control

I think it is Chapter 2 that gives a good intro to the various coupling mechanisms.


Crimp is not my first choice.

My first choice is to tin the bare end of the twisted stranded conductor, trim the end then insert into the screw terminal.

Always neat and clean with no extra parts to fail.

I do the same with set screw banana plugs

Either soldering or crimping is better than bare wire. I suspect that solder is a better option, as there are less connections involved, but doubt that one could hear the difference. 🤷‍♂️
I prefer to use the bootlace ferules if I can squeeze them in. As long as you can get a good and gas tight crimp on the wire, you actually get a better connection with the ferules than without.

So.... its all wired up..no smoke (good start) I can hear music...but volume pot does nothing 😀

Not sure I understand the grounding here... there are 4 grounds in the PCB so I wired 2 together but continuity doesn' work with the other grounds. Anyone got an idiot proof wiring guide?


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You'll want it connected like this:Screenshot 2024-03-03 at 15.06.58.png

Then take OUT+ to IN+ (pin 2) on the Buffer, OUT- to IN- (pin 3) on the Buffer, and GND to GND (pin 1) on the Buffer. The pin numbers refer to the connector pins on the input of the Buffer.

Oh yeah, I think I did something silly :) I grounded both channels I think
I once drew this which makes sense.
Do I really need 2 grounds for each L and R input or can I skip one, the buffer is only taking 1 no?

It looks to me like the ground is done with a plane that connects all the ground pins together. Verify with an ohmmeter. If the grounds are connected together there's no reason to use more than one wire from each XLR pin 1 to the volume control and no reason to use more than one wire from the ground of the volume pot to the Buffer input pin 1.

Hmm the grounds aren't connected, seem to be per channel/ row on the pcb. I cut the wire that I added between the 2 grounds. I have sound but no volume control still
I would either contact the vendor of that volume control for support or measure with an ohmmeter to make sure you have it connected correctly.

Seems you need all grounds wired up... now working.

That was quite a journey but...it works!

Thanks as always to Tom for fielding my idiot questions.
Pride of place on my mod86 (alu finish is a bit nicer on the mod :) )


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You're welcome.

And, yeah. Takachi does a much better job at the anodization than ModuShop does. That's why the surface of the ModuShop panels is a bit grippy. Wipe it with a micro-fibre cloth and you'll find out. :)

It looks like you're using only the XLR outputs of the Universal Buffers, so you could use the single-ended outputs for the sub.