Just to add my 2p -
Re. PTP verses PCB, I also don't think there's any difference in sound that can be directly attributed to the construction method.
I'm pretty sure Matamp make their amps PTP 'cos it;s easy to service, and tweal when you buy one. And also 'cos it's traditional I think.
On the Class A verses AB thing, with my admittedly limited knowledge I'm not sure anyone could say one is 'better' than the other. When at the Matamp factory I asked a certain amp tester

if the Chino was Class A, just out of interest, and he replied that he actually doesn't know, that Dave doesn't design the amps around Class A or A/B.....and that there's a lot of b.sht around regarding Class A being somehow 'better' than AB.
Personally it drives me nuts whenever I see a Class A amp reviewed in a mag and the so-called professional raves on about it's 'fantastic, pure, Class A sound' etc. GRRRR!!
Or when they make a big thing out of how a single ended amp has somehow been designed so you can use any power valve.....GO BACK TO SCHOOL!!!!
Right I'm just ranting now, I'll stop right here!