The YJ20 is for use in most amplifiers using 6V6 output tubes. The YJ20 is similar to the YJC but does not drop the plate and screen voltages. It is meant for use in lower power output amps (20 watts or less) when no power reduction is desired. The ground wire connects to the chassis-ground for cathode-biased amplifiers. All Yellow Jackets® converters come with JJ Brand EL84/6BQ5 vacuum tubes.