GaN amps: Peachtree or LSA Voyager?

reading up on Gain Bandwidth Product, it seems to be present with designs using the bipolar junction transistor. 

@mrdecibel to be clear, all circuits with gain have Gain Bandwidth Product. The question is does it have enough to support the feedback its designed with? If not, there will be a corner frequency where feedback will begin to decrease. This problem has been present in all amplifier designs until only very recently!

If you want the amp to sound smooth and relaxed at all frequencies, its crucial that the feedback be consistent at all frequencies, otherwise its not going to happen.

@atmasphere OK, Ralph, gonna put you on the spot. I wouldn't do this except that you sort of volunteered. The A/Bs I'm talking about are the Van Alstine DVA M225 monos. Surely you know Frank and his products. Care to comment on his matching GBP to feedback? (By the way, this kind of tech stuff is way over my head so I'm not taking a position other than I'm sure you know what you are talking about). 

The A/Bs I'm talking about are the Van Alstine DVA M225 monos. Surely you know Frank and his products. Care to comment on his matching GBP to feedback?

There's no way to tell from the information on the web. But I can tell you this: in conventional class AB amps the distortion numbers you need to see have to be quite low (0.000x), because higher ordered harmonics are a common thing in AB circuits. About the only way you can mask their presence since the lower orders are not available for this is for the distortion to be below -105dB! That means a lot of feedback, something quite challenging to achieve in an AB design. If the amp does not meet this criteria, its likely to have brightness.

@atmasphere

Is there a reference for the -105db? That sounds excessive. Do you mean at a single frequency or all frequencies (I assume 10KHz and under?). I see an often quoted limit of 0.1% as being the absolute lowest than can be detected, and I think normally much higher.

@atmasphere Thanks for the explanation. They are due here tomorrow, so we shall see.