Hi I'm looking to buy a Marshall JMP 1986 MKII. Is 50 tube watts loud enough for practice/club gigs with a hard rock/blues band? I know that it will break up a bit if I turn it up to max, but that doesn't matter, I like that kind of sound. And one more puzzle. It is a Marshall JMP 1986 MKII, but according to the serial it is made in 1983(serial is xxx25R) I didn't know that marshall made JMP's that late, didn't they switch to JCM 800 in '80 or '81?