Problem with biasing

Most likely a bad tube.  Swapping tubes will tell you if it is the tube or something internal.  a bias resistor has been suggested and that would indeed explain the reading but these resistors should last a lifetime.

Running at high bias current will ruin the tube, but it may already be there.

If indeed it is the position and not the tube, then don't run the amp until you get it fixed unless you have a big tube budget.

jerry

Right, I’ll check the tube today. 

It was the tube. I was able to bias them all to .97 volts… that right, what would that be in ma? I have 2 amps for a bi amp system. Yea one is in ma and the other volts? I like if they’re 85 ma

😊👍

Tube problems are not common, but if you get a whistle, bright tube, or weird poping, that is the place to start. Because most tube equipment uses more than one of the same tube, diagnose can take a couple minutes. 
 

My systems run over forty tubes and I get a strange sound every couple years or so… typically associated with a new or relatively new component. 

Wow, 40 tubes, that’d be expensive to re-tube I bet. What are you running?i