Tube socket votages

white room · Post by **white room** » Fri Nov 05, 2004 8:57 pm

Ok, I am at the point here where I'm checking my tube socket voltages.

The heater voltages look fine across the board, but the voltage chart tells me I should have 200V on pin 6 of V1 but I'm reading up around the 400V range on pin 6 for V1,2,3 so what might be causing that? I've triple checked my wiring and everything looks good. I must have miss something

5150loveeddie · Post by **5150loveeddie** » Fri Nov 05, 2004 10:16 pm

Hold everything up and let George or Jon reply to you.......this is not normal!

Flames1950 · Post by **Flames1950** » Fri Nov 05, 2004 10:45 pm

Is that with the tubes in or out??
I've read funny stuff on my amps with the tubes out (no load!!) that read fine when I put the tubes back in place.
Just a thought.

white room · Post by **white room** » Fri Nov 05, 2004 11:30 pm

That's with the tubes out.

I'm reading ~ 490V on pin 6 of V4-7 which I would assume could be normal without the tubes in place but this 400v+ on the preamp sockets seems way too high to me. I could be wrong though. I have never done anything this exstensive on this amp before.

I am really missing my amp

I hope I can get this problem resolved.

Flames1950 · Post by **Flames1950** » Sat Nov 06, 2004 1:31 pm

Try measuring the voltages with the tubes in. This is exactly what I was getting on my amps with the tubes out, preamp plate voltages looked way too high, but since there's no tubes drawing current you're not dropping any voltage anywhere in the circuit (at least that's the only explanation I could reason out.) After I put the tubes back in so that current was being drawn through the circuits and the voltage was dropping on the 10K resistors and tube plates I could read the normal voltages as expected.

Guest · Post by **Guest** » Sat Nov 06, 2004 1:43 pm

That's the same conclusion that I'm coming to because everything else seems to check out fine.

The only thing that keeps me from putting the tubes in and checking the votlages is that I am only reading about 20V higher than what the charts states on the power tube sockets for the plate readings which would support the "no-draw" position and I don't want to turn my preamp sockets into launch pads for the tubes

white room · Post by **white room** » Sat Nov 06, 2004 2:04 pm

Whoops!!! guess I'm a "guest" again

I figured out that I have to log in twice, It doesn't "take" the first time