So does that mean it uses digital/relay control for actual volume, and the stepped attenuators are just for balancing?
I think perhaps the relays switch from one attenuation level to the next attenuation level [as I don't see a motor], similar to a TAPX, except that the actual component performing the attenuation here is a resistor not an autoformer or transformer. So the quality of the resistor becomes UBER important but tweak able, which is why he has choices of AMRG, Vishay SMD, Takman, etc...depending on budget. But dual motors would do the same job! Perhaps I should email him n the actual mechanism...
His prices are actually very nice for what he is trying to offer from a "looks" standpoint, but there is competition from Tortuga, TAP-X, Django, etc...lots of choices for us audio geeks which is great. I hope Tomy2Tone will chime in on the sonics soon.
The basic component is a Khozmo attenuator in this unit.
Balance "control" is provided by changing the attenuation levels relative to Left and Right channels. So if the level on the right is 42 and the level in the left is 40, your center will move to the side that is louder or less attenuated.
Best,
Anand.