EL 509, Tube EL509; Röhre EL 509 ID18745, Beam Power Tube | Radiomuseum.org
JJ EL509 Datasheet 2005 - Dr. Tube
OTL is the way to go for audiophile hifi as long as reliable EL509 tubes are available. 6C33S is just too power hungry and the 6080… | Audiophile, Hifi, Vacuum tube