I have a pair of monoblocks configured as two PP amps on each chassis with the OPT secondaries in parallel for ~ double the power. The amps work very well, and sound great.
If I fire them up and let them sit for a minute or two and then bias all the tubes to 33mA or .330V, they will hang there for a while. If I come back in a few hours, some of the pairs will stay locked in, but some of the other pairs appear to be unbalanced as much as 20-30mV. i.e. .320v and .343V or something like that.
They are Chinese 6L6GCs. Is it possible that it is just the tubes? Is it something I should worry about?
Thanks!
Blair