Jive Turkey -- I got your PM, and just read your post, above. I am not surprised that the "circuitry around the volume control knob looks like it is digital". However, it is what that digital circuit actually does that matters. The output amplifiers are all analog. All of the incoming digital signals are converted to analog before they are sent to the amps. The digitally controlled input switches select which audio signals get sent to the amps, usually through a buffer circuit which isolates the various inputs from each other. This buffer circuit also contains the volume controls for each channel.
Each volume control is one section of an 8-gang logarithmic taper potentiometer (the actual volume controls). The 8-gangs are driven by a small servo motor which is driven by the "digital control" circuit that the "rep." found in the service manual. He just didn't look far enough into the schematic pages (easy to do if he was not a service tech or electrical engineer).
There is another alternative, which requires more parts. That method is to use stacked resistor arrays which provide the correct resistance ratios needed for each "volume" step. The parts count can be reduced, somewhat, by using integrated circuit (IC) resistance array segments. However the resistance ratios have to be fairly precise, and one pair of resistors, per channel, is needed for each volume step. As an example, to go from -30dB to +6dB, in steps of 1dB, requires 36 pairs of resistors per channel. For 8 channels, that means 36 x 2 x 8 = 576 resistors.
If they can buy resistor ICs with 12 resistors per IC, that still means 48 ICs (that was the state of the art 35 years ago). Hopefully, they can cram more than 12 resistance elements into a single IC by now. For every 5dB of added range, 80 more resistors (8 resistance pairs per dB of gain) are needed. The resistors have to handle the maximum signal level that is being input to the volume control circuit. At one time I was toying with the idea of designing my own amp. This method of volume control was interesting, but the number of parts needed (and the cost) was prohibitive, at least on a one-off basis.
I have not seen those schematics, nor do I work for Pioneer. However, my description is the way I would have designed the VSX-94, if I were to use a "digital volume control". Using a simple mechanical connection, would have been significantly cheaper, but not as "elegant". Of the two alternatives I described, the one that has the least cost is the one they used.
The bottom line is that the actual volume controls are not digital. They may be digitally "stepped", but they still are working on an analog signal (in the analog part of the VSX-94THX).
