[mrkenny]

I'm not a wiz when it comes to amp stuff but I do understand Biasing an amp. I have an amp tech friend, I had him install a bias pot in all my amps. When I want to check/change power tubes I always use the meter (ordered from Allesandro). My Meter has tow sockets and corresponding VU meters. Remove the tubes, and plug the sockets in the amp then re insert the tubes in the sockets. You now have the bias meter in between the amp and tubes. Turn on the amp and the VU meters will rise to the appropriate "Ma" reading. A matched set of tubes will read within 1-2 Ma of each other. My Bassman's 5881's should be set between 31-35 Ma, I set them at 32. If the tubes you are installing read to hot or weak just take a small screwdriver and turn the adjustment screw on the bias pot clockwise or counterclockwise to bring up or reduce the current, very simple. Like stated in previous posts, biasing is like tuning up you car.