Hey all, I have a JoMama Keleman Reverb 45. This is such a GREAT AMP! This amp can take anything from 6v6 to KT-66's to EL-34's and therein lies my question to you all. I have been swapping out tubes and re-biasing properly, no problem there. I am bewildered about my GT KT-66's. When I bought them, they were a matched set, I would set the bias at 35 for the higher reading tube and the other one would read out at 33. This is a difference of .002 and that is what GT calls a "matched set". It all sounds great so no problem there. I have been switching out with a set of EL 34's and of course their reading of 40- allows much more current flow [I assume]. When I switch back to the KT's and reset my bias one tube is reading out at .005 different than the other tube. This happened once before and the tubes worked themselves out [I guess] and settled back down to a "matched" difference of .002, that was a couple of months ago. I had since gone back to the EL's for a few weeks and again went back to the KT's tonite. The KT's are not "settling" out after a couple of hours now as I am still getting a reading of .005 difference. I do handle the tubes properly etc. etc. so I know that it is not from misuse or mishandling. First off, is a difference of .005 going to do some damage to my amp components? It sounds just fine, but I do not want to be quietly creating a problem for myself here. Can you offer some feedback, positive or er...."negative"? Sorry.....Thanks in advance. M.E.