need help tweaking a bias circuit

[pbman1953]

Traynor YBA-3A- with KT -120's


The 120's work but I need help tweaking the bias circuit to bring down the cathode side.


Here's the layout-


http://www.0rigami.com/vb/YBA3__cool-schematics.gif




At this point here are the values in the amp now:


C24 & 25 are 10uf


R36 is 3K.


R37 is  47K


The bias pot is 20k




The highest tube is 81.6 (IK)  and the lowest is 73.8 (IK).


I've been decreasing R36 but it seems to creep back up. The pot is pinned and measuring "0" on my ohm meter.

Any thoughts?

[sluckey]

There is a 130K/2W resistor shown just above the PT. Change that to 100K and see if the cathode current doesn't decrease.

[pbman1953]

The 130K was really a 150K. I tried the 100k and it cut it too much and  now I'm at 135 with  22k resistor from 3K.


Thanks!!!