Fender Bassman 50 & 70 ECC803S Option

1972 thru 1983 Bassman 50 and Bassman 70 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. If your amp still has the stock "balance" bias circuit we highly recommend modding it to be fully adjustable bias.

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

You can use the Deluxe Reverb bias video for reference. We typically bias Bassman's between 36 to 44mA with the JJ 6L6GC's or 33 to 40mA for 5881's.