Low voltages

[distorto]

Hello.

I've been working on converting an RCA console amp to a one channel 5E3. I've got it running and I'm wondering about the best way to deal with my voltages. I seem to have too little in the power amp section:

327 vdc at recto.
303 vdc after the 5000r
252 after the 22k

6V6's

pin 3 319
pin 4 307
pin 8 17.7

pin 3 324
pin 4 306
pin 8 17.7

Cathode resistor is 250r


12ax7s (I don't have a 12ay7 in V1)

V1

pin 1 159
pin 3 1.5

V2

pin 1 180
pin 6 217

My filter caps are 40uf/40uf/20uf (all 450 volts) If that makes any difference. They were what I had on hand.

Any insight would be greatly appreciated.

[tubeswell]

What sort of rectifier have you got in there? If it is a tube rectifier, unplug it for a moment and measure the VAC on pins 4 and 6. That should tell you whether the PT has got enough juice (~320-325VAC on each side) to get you into the 340-360 Zone with a 5Y3GT rectifier. If it hasn't, you may want to put in a 5V4 or a GZ34, or just use diodes (which may give you more than you need)

[distorto]

Thanks for that.

I have a NOS 5Y3 in there now. I get 326-326 vac on pin 4 and 6 with the tube pulled. I have a unmarked rectifier tube here that gives me better voltages. It looks like a GZ34 but it warms up slowly. Any idea how to identify this tube? Also with this tube in my preamp/PI voltages get a little high:

V1:

pin 1 184

V2:

pin 1 204
pin 6 243

If I go with this tube should I adjust the 22k dropping resistor? I also have a NOS 5u4 GB but that would probably draw too much heater current?

Thanks a bunch for your help