20watt resistor on EH150

[gary sanders]

I have a small amp I built with a SE EL84 in it and used a 1k 10w to drop the B+.I put it from the first filter cap to the first in the dropping string.Would it be better if I had a larger R value going to ground like the 20k 20W on the EH 150?

(There was a thread way back when I was asking about the high voltage on the EL84.Without a resistor the plate voltage was around 300 and Id like to get it down to the safe zone for the EL84.The way it is with the 1k 10W still has me too high at 270 plate volts)

[alvarezh]

Hi Gary, 300 plate voltage on El84s is fine.

Here is an excerpt from another forum regarding EL84s on a Mesa Express 2:25 :

"I have a set of JJ EL84s that are rated 31ma and a set of RI Mullard EL84s rated about 34ma. The Mullards I'm not crazy about, the JJs seem the closest to the original tubes as far as when they break up and distort. I'm thinking I want to go down to 27.5 for 10.5 watts. Right now, if in spec, the V on the tubes in PP should be 382. So, with the 34ma the math says 12.98 watts, too high IMO. The 31ma says 11.84 watts, right on the edge. 27.5ma or so would be down at 10.5 watts."

I run my 84s @300 plate voltage, although JJ specs calls this "maximum allowable".
Never had any problems. It's my understanding the guys on the Trainwreck (Liverpool) side of the forum run them @325 volts.

I have read a few lines about the optimum voltage use on the 84s, and most experienced tech's answers were that there should be no problem running them (voltage wise) above factory specs (to a limit, of course), what they stated to be VERY important is the bias setting, DON'T overheat them!

All the best.