Ayre Acoustics KX-R Twenty Preamplifier.

Ayre Acoustics writes: "Ayre Acoustics KX-5 Twenty preamp variable gain circuit in progress. Each channel gets 46 resistors, and each one is engaged by a silver to silver, solder-less contact, by way of an electric stepper motor to select the specified volume position. It’s as close as you will get to having your own private electrical engineer asking “what volume would you like?”, and point to point wiring it in. Another bonus is a consistent signal to noise ratio at any volume… Decidedly different; because it sounds better."