Years ago I remember working on a tube amplifier that used EL84/6BQ5 output tubes in push-pull, but instead of applying about 300 or 400VDC to screen grids and plates, the plate circuit went to chassis ground and the cathodes were operated at a high negative voltage. Naturally the sound was just as good as the more conventional approach. I tried some searches for such an amplifier and so far have not been able to determine who made such an amplifier.
The cathode circuits of the outputs had electrolytic capacitors to bypass that circuit installed in reverse polarity from that seen in most amplfiers, as did the power supply which used solid state rectifiers. There was also a negative bleeder circuit for the heaters of the output tubes to help avoid cathode to heater shorts.
Do any of you remember who made such an amplifier?
Joe