[cactus_farmer]

Are THX/Topping feedback correction amps a type of class A, or class B or class A/B, or class D amp?

 

[TrumpOrMonkey]

They're almost always class AB, though Topping has managed to create some Class D speaker amps which measure great too. Though it's not impossible to create a Class A amplifier which measures well especially if you use an op-amp input stage (where the vast majority of negative feedback can be applied), like the RebelAmp for example (based on the AMB m3 design). But there are cases like the Flux Labs amplifiers where they don't even use an op-amp input stage and still measure very very well. But if we are talking 120db+ THD+N designs (and not just stuff that comes close enough that it doesn't matter) then they will almost always be class AB.