Yellow Jacket Cathode Biased Triode Tube Converter For 6L6 / EL34 / 6V6 / 6550, Duet Yellow Jackets converters allow you to harness the musicality of EL84 vacuum tubes in amps that don't use them already - it's like getting a whole new amplifier! This model of Yellow Jackets converter, the YJC TRIODE, is a specialized, current-limiting/voltage-conditioning adaptor for use in most 20 watt to 100 watt amplifiers which use 6L6, EL34, 6550 or 6V6 output tubes. Yellow Jackets converters give you simple Class-A operation from any amp. Drops Output Power about 70% to 90% Hand Built In USA Converter + JJ Electronics EL84 Tubes (Duet)