Class H amps?

https://www.youtube.com/watch?v=Zl0vP62WpLI

The output transformers are valves between 2 voltage rails. Say, + and - 10 V.

In A, B and A/B those rails are fixed values. Classes G and H vary those rail voltages. Carver and NAD got famous on G. The idea is that minimizing the difference between the rails and raising them only when needed minimizes heat of the output transistors.

NAD continues to dabble with their hybrid Class D amps today.

Wikipedia is your friend:

As an aside, an audio buddy is using a pair of Benchmark AHB2 Power Amplifiers to drive his SoundLab electrostatic speakers to great effect.

H is good.

D is a muddy mess.

My Sunfire sig 600 is class H, and smokes much if not most of the newer amps at lo local shop. They are sick of me showing up with it, and besting much of their high class amps. Im thinking's soon they will ban people from bringing in their stuff for speaker auditioning.