fenderiarhs
Active member
I just bought a marshall jcm2000 tsl601 combo...i know it's not the best out there but i have had enough of carrying head+cab on gigs. It comes with the ecc83 tubes in the preamp stage and some el34 on the power amp. I was thinking of replacing both.......the preamps ecc83's with 12ax7's (is there going to be an improvement in tone using the 12ax7?????) and the el34 with some better quality el34 tubes.....When going from ecc83 to 12ax7 in the preamp department is there any need of biasing or any other modification?Swaping the power amps el34 needs biasing? Thanks for any responces