Vox ac100cph Bias questions.

Hello, I have a Vox ac100cph and I am throwing in some new tubes they
are electro-harmonix el34's. I have some questions.

On the back of the amp there is a cover over the bias adjusters. there
are 2 bias adjusters and above them are 3 pins that are sticking
out.

1. I am wondering how I can tell what each pin does without ripping it
apart. There is nothing in the manual or the net that I could find. I
am assuming they are test points but why 3 of them?

2. I stuck a volt meter in pin 3 of the first tube socket and touched
one to ground and it got a reading of 1661Vor so do I take that number
and divide it by four to get my plate voltage? This is the first time
I am biasing an amp.

3. do I need to add a 1ohm resistor to the tip of my meter to get the
correct number on the test points.

Thank you for your help.
.

Relevant Pages