WHAT, HUH, Hmmmm.... Sorry, musta dosed off. I decided to build the Angela/JE Labs 2A3 Simple. Then one engineer friend of mine looked @ the schematic and thought I should be able to run 300B's off of it by adding a Tamura filament transformer and a switch to go between parallel and series which indeed does change the filament voltage between 2.5v and 5v. It's starting out stock running the recommended 6SL7's but another friend suggests reworking it to use 6W6's. Don't forget, it should be able to play 45's, (NOT the early 60's discs), as well. I'm just an innocent pawn in their games.