EL84 Triode PP Design

[sorenj07]

I have the EL84's, the OPT's, and the 6N23P's are on the way.



Power supply:
Hammond 273BX (350-0-350 175mA) rectified by two UF4007 per leg bypassed by .1uF 1KV, into 193M choke (10H 300mA 63 ohms) and 440uF 450V cap, bypassed with 1uF 630V, feeding B+. B++ taps off a 20H 20mA 1.67K and 100uF 400V bypassed with another 1uF 630V, for the two 6mA regulators at 275V. The C- supply is a voltage doubler running off the unused 5V tap.

Is tapping off the -15V supply for the LM334 CCS reasonable?

[mesherm]

I used a simple resistance voltage divider in a -12 dc circuit to apply -5 vdc to the negative term of the lm334 on my PPP EL84 amp. I also wired a UF4007 diode in series with each screen grid resistor with the banded end toward the screen grid. That allows the DC to be applied to the screen but blocks AC loss and improves the power. I have done that on every triode connected amp I have made and it works well.

[sorenj07]

Is there any way to get 5mA+ through the 6DJ8s other than to use a negative voltage supply? I'm looking at doubling off a Hammond 166G80 (80V .5A) for a -210V supply, which, with a 21K 5W tail resistor, should spit out 10mA for the cathodes to share right? My plate resistors would be 24K 2W.

I assume that a LM334 won't like putting out 10mA very much...

About the bias adjustment setup: would a 10K pot and 5K resistors to ground work better?