Fender Bassman 100 & 135 ECC803S Option

1972 thru 1983 Bassman 100 and Bassman 135 amps are not fully adjustable, they have a balance circuit where one power tube is adjustable so all you can do is match the bias to the fixed power tube. This can be done using a bias probe and a multimeter or one of our "Pro One" bias probes. 

All of these are are available in the "Related Products" tab. 

The best solution with these amps is to mod the bias to be fully adjustable. Over the years many techs have been doing this by default. If your amp has been modified you can use the Deluxe Reverb bias video for reference. We typically bias these amps between 35 to 40mA with the JJ 6L6GC's or 33 to 40mA for 5881's.