I feel that Bear is getting to the right point. Far not every brand giving out circuitries but yet I'll get in touch with the manufacturer as suggested to educate myself.
I remember a long time ago reading a Bryston 3B-ST ciruitry that is using an active neg. feedback stages that do not reduce the input impedance(more sophisticated than gain stages)!
In SS case most of the powerfull amps are multistaged especially class A designs since they tend to keep all amplification elements in the small signal operation(prepare to manufacture some power plant for such amps!)
I remember a long time ago reading a Bryston 3B-ST ciruitry that is using an active neg. feedback stages that do not reduce the input impedance(more sophisticated than gain stages)!
In SS case most of the powerfull amps are multistaged especially class A designs since they tend to keep all amplification elements in the small signal operation(prepare to manufacture some power plant for such amps!)