gadjet
03-07-2009, 03:07 PM
I have a Twin that I think was bias'd cold... I picked up a amp-head biasing cable and have my digital VOM that reads out in Mv.. The tubes are Fender labeled 6l6s but they are Sovtek 5881 WXT... I hooked everything up and it read 1.0.... I fiddled with the bias control and I could get in to 21.1 Mv upper range and 1.0 Mv lower range... My under standing is that 1Mv = 1Ma with this method... Recommended bias for the Sovtek is 37 Ma... On my VOM I currenty have a readout bias(on my meter) of 3.6 Mv... this is about half the travel of the bias pot.... Do I have a amp problem? or is my meter just reading strangly? the bias trim pot works quite well and I can actually feel the tubes get warmer/colder.