I was sent this and it was posted on SBAF so one can expect the level of discourse over there:
There is so much here that I don't even know where to start. First off, they claim this circuit is "unique"...well it isn't. Old as the hills this one, same as the old TubeCad stuff, the Rudistor amps, the prototype Schiit built, that Trilogy H1 piece of shit and I've been building similar amps for the last 15 years. Stax also released something similar in the 60's so no...not unique.
The amp circuit is simple and works well enough for a cheap amp so nothing wrong with that. I also like that they used a CCS on the front end (though they claim it is on all stages but that's not true) but my issue is with the PSU and the bias supply. What an utter clusterfuck.... The circuit requires a bipolar PSU so with a center tap transformer the bias supply can be a bit tricky but simple to solve really. I just don't understand what the hell they did with that delay circuit. It's just adding tubes because... tubes? Makes no sense at all.
The bias supply seems to be driven off a tap for some reason. Also, those ballast resistors look like RN55 units and they are nowhere near adequate for the job.
Smaller issues, twisted output wires are a no no, not sure what's up with those output "sockets" and an unregulated heater supply is never a good idea. Still I like the colors. Might have to do something like that...