Tube Amp Doctor (TAD)TAD is a German company established in 1993 which selects and matches electronic tubes and manufactures musical instrument accessories.
Bias Master™ system BM4 Measures Bias current of the vacuum tubes in your amp. Includes 4 probes and english/german operation manual. The Bias Master™ allows you to monitor the bias current safely and easily. While adjusting the Bias control pot of your amp, the Bias Master™ shows the actual result. This lets you set and evaluate the full reasonable biasing range your amp and tubes offer to find and set your personal perfect choice.
Package of 2Bias Master™ set of adapter probes for testing other types of tubes. For use with the S-TBM4-X Bias Master™ system.
Starting at $63.63