Here's the inside picture of our stepped attenuator we offer as an optional upgrade for all of our amplifiers.
These are 24-step, ladder-type attenuators. Ladder types are by far the best performing type of attenuators and are made with no audio compromises, unlike shunt and series type attenuators.
The downside is that they require twice as many resistors to build because each step is its own volume control circuit with only one resistor in series with the signal path.
Our attenuators are hand made in house with 92 Vishay/ Dale Military grade, ultra-low noise and a rugged, silver plated 24-step attenuator switch.
EDIT Feb 27, 2018:
We got a bit better at making our attenuators over time, so I included some pictures on how our new 24 step attenuator is made (this one comes stock with all amps)
This is just a bare switch
This one has its first row of resistors soldered in. We clip the leads and then do the other side.
This is a completed attenuator, tested and working perfectly!