You know there is a a lot of talk on bias, cool leans out the sound thin, quack quack , to hot shortens tube life and runs hot . I've found that there is a sweet spot for biasing valves. It actually SOUNDS better. Again not just a little. I use these from 300hz UP, no bass duty at all.
A Mac TEC, usually doesn't bias stuff after it's set up. Set it and forget it, its one of the good things about a Mac, BUT I have a 240 you can. AB (push pull amps) not so critical, Class A, it makes a BIG difference, AB too, if you really listen, just not as dramatic.....
So The R has the better transformer and the 12XXX.
What about the monoblocks? same. Ver 1.2.3 ? Kinda rare for sure.
A Mac TEC, usually doesn't bias stuff after it's set up. Set it and forget it, its one of the good things about a Mac, BUT I have a 240 you can. AB (push pull amps) not so critical, Class A, it makes a BIG difference, AB too, if you really listen, just not as dramatic.....
So The R has the better transformer and the 12XXX.
What about the monoblocks? same. Ver 1.2.3 ? Kinda rare for sure.