Note: This board has never been mass produced. The demand is not high enough for affordable duplication. The circuit is simple enough that perf board construction or point to point wiring can be used. The schematic and pictures are posted here for those who desire to make their own.
I have had a few people e-mail me asking if I could make them a PowerDrive board,
The driver board also called the heat sink board is shown here mounted to a large heat sink. The components on this board dissipate about 30 watts total. Most of that is in the two power resistors. Conventional power resistors could be used without a heat sink, but they are large. The board contains two (stereo pair) PowerDrive circuits on a common board.
The PowerDrive board mounted in the845SE amplifier
Two of everything except the tubes and voltage sources is on this board.
See the PowerDrive page for theory and circuit details.