Converts most audio amplifiers with 6L6s, EL34s, 6550s or 6V6s to EL84s without modification or rebiasing.
I have actually been using them in guitar amp, but they will work in any amp that uses the 6L6, 6V6 or EL84's and turn it into a cathode-biased class-A circuit running EL84. Changes the tone to a very mid-range rich detailed sound.
They retail for $59 for one.
The pair of adapters comes with the matched Sovtek tubes shown.