Robin - Yes, the SmartSubs are Class D. Jim began working on those amps with a very talented designer at/from Vifa in the late 80s. They put quite a bit of sophistication into those designs, which were done in the early dark ages of Class D. Impedance requirements are less of an issue when the entire amp-speaker is modeled in toto. I use a single SS1 and a pair of SS2s in my studio and love them. I am searching for a good repair solution for them.
I have heard that Jim considered Class D suitable only for bass due to inherent topology constraints. But, a lot has advanced more recently. I have heard recent pro-audio class D amps, and I would not consider such for my music use, just because, no real experience, but an inclination toward a topology with more inherent wow. I am intrigued by what PS is doing (thank you ronkent) . . . a tube input before a mosfet output stage seems potentially great.
Regarding Pass, Nelson is a brilliant designer in my opinion. Pass and Thiel shared equipment and insights beginning in the late 70s. I would expect Kent's opinion about synergy to be extremely well-informed.
I have heard that Jim considered Class D suitable only for bass due to inherent topology constraints. But, a lot has advanced more recently. I have heard recent pro-audio class D amps, and I would not consider such for my music use, just because, no real experience, but an inclination toward a topology with more inherent wow. I am intrigued by what PS is doing (thank you ronkent) . . . a tube input before a mosfet output stage seems potentially great.
Regarding Pass, Nelson is a brilliant designer in my opinion. Pass and Thiel shared equipment and insights beginning in the late 70s. I would expect Kent's opinion about synergy to be extremely well-informed.