If anyone can offer some support on biasing my Sunn 300T, it would be appreciated.
I blew the middle 100ma/250 volt fuse that protects the power tubes. I ordered new fuses, changed the blown fuse, and the cooresponding pair of 6550c's. The amp was loaded with the original Fender/Groove Tubes power tubes. I replaced the middle pair with two Ruby Tubes (from a matched quad set). I know Ruby Tubes aren't the best, but they are what were available. Here is where my problem starts.
When I biased the amp, the manual read to set the voltage to 0.1 VDC, but the closest I can get is 0.082 (the bias screw is maxed clockwise).
When balancing the amp, he manual says to set the voltage to 0.000 VDC, but the closest I can get is 0.002 (the bias screw is maxed clockwise).
Any suggestions on what I do next? Swap the tubes again? Change another pair of tubes? Am I "close enough" or will I damage something?
Here are links the the manuals, both say the same thing.
Page 10 http://www.sunnamps.com/pdfs/manuals/bass/300T.pdf
Page 8 http://support.fender.com/manuals/ba...ead_manual.pdf