Re: Marshall Bluesbreaker RI
I think they are very good pro gigging amps for most anything short of modern metal. I like them better than the Tweed Bassman re-issues which are also PCB but usually don't have the valve rectifier. The BB are well built by modern standards with chassis mounted tube sockets and pots with flying leads. If they were true PTP they would be much more expensive.
The name Blues Breaker comes from the fact that Eric Clapton used an early 2x12 combo version of the JTM45 with a Les paul to record the classic Blues Breaker's Beano album.
The re-issue comes loaded with ri Greenbacks and has some minor differences from the originals in terms of the bright caps and mix resistors..ect... and also the output transformer. Its pretty common to replace the 5881's with KT66s, or EL34s in some cases, and the GB speakers with Alnico Blues (they typically put out 27-35 watts). More involved mods may include putting the resistor and cap values to original spec and a Mercury Magnetics OPT, but stock its still a good amp.