I have a few GZ34 tubes. The amp has 2 x 6L6GC power tubes (Vibrolux). I monitor the power tubes with a Weber Bias Rite and notice that, when using one particular rectifier (Japan made RCA), that my output -ma fluctuates, i.e., when the amp is idling the power tube measures -42ma but when I hit a strong chord the output goes up to as much as -46ma. When I tried a used Mullard GZ34 the output tube doesn't move much from it's idle current during attack. Both tubes test very strong. I am just wondering if there is anyone who can explain which scenario is better or if either scenario are ok? The fluctuation is not very much, maybe 2-3ma with one tube and 1 ma with the other. I am guessing the tube that moves the least is not being taxed and would be the better tube? Also, I run 2 x RCA 6L6GC tubes. Is there a general "best" setting for bias? Right now I am running 2-3ma apart. One tube is 42ma and the other is 44.7ma. thanks