I can speak to the HX/DA amp, since I have one, but I believe that the other USA amps are made this way, too:
On US amps, there are no PCBs -the amps are hand-wired to an eyelet board with premium parts. All of the tube sockets are chassis mounted. The chassis are aluminum. Here's a gut shot of the amp (I found this elsewhere); you can see the hand wiring of parts, the flying leads to the controls, etc. The tube socket mounts are at the bottom of the chassis as you look at the picture, and as you can see, the sockets are attached to the chassis and are well away from the other parts, which should add to the longevity.
This is a great way to build an amp, and IMHO a hand wired amp made like this has a certain clarity of tone that is quite wonderful. It's a first-class boutique amp, the real deal in every way. Of course, the controls are also chassis mounted. No corners were cut, anywhere.
I think the short flying leads have something to do with the tone of the amp as well, as opposed to creating longer leads and twisting them, just to make things appear tidier.
I realize that PCB amps can also be great - I do like Mesas, for example - but they sound a little different, too.
There's probably no categorically right or wrong way to make an amp if it sounds good, but you can hear the quality in this amp.
I've had a number of more expensive hand wired boutique amps, like Two-Rock and Roccaforte, as well as high quality PCB amps like Bogners and Mesas. And of course, I've owned vintage hand wired amps in the days when they weren't vintage! I really believe that the PRS amps are at least the equal of anything out there, and for my purposes, they're the best I've had. I feel very lucky to own one, and business permitting, I'd like to add a second one to the studio next year.
