Yellow Jacket YJS

The YJS is a specialized, current-limiting/voltage-conditioning adapter for use in most 20 to 100 watt amps that use 6L6, EL34, 6550 or 6V6 output tubes. It converts these tubes to EL84. The YJS is for amps with fixed bias power tubes. (Fixed bias tubes have their cathode connected directly to ground and a negative DC voltage applied to their control grid).

There is no rebiasing involved, which makes modifying your amp's tone very easy. Yellow Jackets