Patent ID: 7551025

Claim:
A high-power transconductance circuit (HVTC) comprising three direct-coupled stages which can be substituted for a final-stage power-amplifying vacuum tube in an audio amplifier, the input to the HVTC being a composite signal consisting of an AC component and a DC component, the HVTC comprising: an output stage which utilizes one or more power transistors to drive a load; a driver stage which transforms an input signal consisting of an AC component and a DC component into a driving signal consisting of an AC component and a DC component for the output stage; an input stage which conditions the input composite signal for input to the driver stage, the input composite signal being direct-coupled through the input stage and the driver stage to the output stage, the DC component of the composite signal being independent of the AC component; and a power conditioner for supplying regulated power to the HVTC.