P.I problem

[Johnd]

I have a voltage problem in my P.I. I am getting really unbalanced voltages on the plates one is seeing 205 and the other 300 or so. I want about 245 on each. Also the grid pin 2 P.I. input is only seeing 18v. It should see 65 or so . the cathode voltage is also low.All other voltages are correct in the amp, power and pre section and bias. The B+ is correct, about 315v at the P.I. before it hits the 100k split. I have replaced everything in the P.I. and coupling caps to the P.I. and from the P.I. no luck. Any suggestions. The amp sounds good but has no drive like it should.

[servant]

Also the grid pin 2 P.I. input is only seeing 18v.

You may have the first 18 watter with 18v.

[Plexi]

I would check the value of those resistors,it sounds like you've used a wrong value,and a very easy mistake to overlook.. Also make sure you have the right tail resistor value in the PI.. and it is tied to ground. Also an unbalanced tube can have different voltages,but that sounds a bit far off for that,still worth a try to use a different tube and check voltages again. Is this the stock 18 ? can you post some pics for us to see,it helps to have a look,and better to troubleshoot. Sometimes we can see something you might overlook.
Be sure you checking the right tube for voltages, V3 or trem channel voltages will be alot different on each side. Just a few things i can think of.
Richie

[Johnd]

It is a min. 18 watt. one channel w/ a volume. one input tube paralled to the vol then straight to the P.I. via .022. I had stock values in the P.I. measured everyone. all checked good. I started replacing parts one by one. The after lots of changing I replaced everything to the P.I. mod (vox style one) same thing. Replaced every resistor in the P.I. execpt Grid resistors to the El84. Also every cap. tried lots of tubes.???

[markh]

As Richie said, a picture might help.

--mark

[Johnd]

I'll get a pic together . My layout is diferent that all of you. I used point to point...no board.