This can't be right. I just gor some of the shuguang 6l6's and couldn't get them to go any higher than 32.8 ma @ 458 V on the plates. The bias pot tops out there. So I pulled the tubes and checked the -DC voltage on the control grid...-49V to -60 volts. Could my resistor have drifted this much? I'm amazed the guy I bought this froms tech didn't catch it. Could it bee something else?