Amp has 550v of B+. What screen resistors for JJ E34L's?

[Nigel]

Have 1K5W in now, but one socket runs hot and that one kills tubes in less than 6 mos. consistently.

1.5K? 2K? I like smooth, big, hard rock tone.

 

[Nigel]

The JJ's can only take 450 volts on the screens according to the data sheet. The 1.5K screen resistors are pretty big but not at all unheard of.


SED's are the only tubes I know of that can take the high screen voltages (500v).

Most people talk about plate voltages, but the design spec for EL34's is 800 volts on the plates. It is the screens that are the weak point.

The Shuguang EL34BHT's are supposed to handle high voltages on the screens (500+) but haven't tested that too much.


Id the 550v under load? tubes installed. Or measured without tubes installed.

Does it have 2 EL34's or 4EL34's.

One particualr socket is of interest.

550 under load, sags almost 100v at volume when digging in. 2 EL34's. It's a zInky Mofo, btw, and was built for the Sovtek 5881.