Apologies in advance for what may be a stupid question, but I'm relatively new to vintage amps. I have a nice 1959 tweed deluxe but would like to swap out the Groove Tube 6v6s it came with; I hear that RCAs sound great in this amp. Will I have to re bias the amp? How will I know it? If something is out of whack, do I run the risk of damaging the amp or injuring myself? Thanks.