OK. Pic is below. It was my first implementation a few years ago, and I have another that was a little more cleaner (on a PCB) that I want to keep. It is powered off a 9V battery and dropped to 5V via a 7805 regulator. It is a single pot design. Its a bit of a rat's nest, but sounds very clean - no hiss or hum. You can also use a 12V wallwart, but since there is no sink on the 7805, may get a little hot.
The first quarter turn from 6:00 to 9:00 does nothing as far as attenuation, but then both channels tracks pretty close after 9:00 all the way to full volume. As you know, there is no gain on this volume control.
Probably a good candidate for a re-house into something a little nicer.