JTM45 Bluesbreaker question

[Taz5150]

I am lucky enough to own what i consider to be a cracking good Marshall re issue of this amp. The stock 5881's are fine to me but with the re emergence of KT66 tubes everywhere thanks to the VM do i get the option to change the tubes like for like?? The 5881 is basically a 6L6 and i believe the KT66 will fit straight in. Obviously the amp may have to be re biased, but i also cannot see anywhere on the net how to re bias this particular re issue??? I do rebiase my TSL, VM and Fender Twin (sorry!) so i am not without some technical ability. My JTM re issue is also the larger cabinet 2x12 so the previous reported space problems are not apparent. I would appreciate some advice !!! Regards Rob

[slowpokerhino]

Well, I can say that I know it can be done.
Many years ago I had a bluesbreaker RI that the previous owner had put KT66s in. Not sure what all was involved in the changeover though.

[LivewireBlanco]

As far as biasing, the reissue is just like the original in that it doesn't have a knob to adjust the bias inside. You would have to change resistors or put in your own knob.