The schematic shows the measurement at the point where the yellow cable comes out of the PCB but at this point the cable is protected with hot glue, so I took the measurement from where the yellow cable meets the tube socket (is this correct?) it read 27.8mv/ma (assuming this test point has the 1ohm resistor over it to assist the mv to ma conversion?) Last night I took the amp out of the cabinet and took a few measurements.īased on the PRRI schematic, I took measurements at TP16 and TP17 for the cathode current. Also, unless I was to purchase a dual socket probe, this feels like it will be a bit quicker (and I will learn a bit more!) I am VERY careful around these electronics and understand lethal charges etc etc. These items are very hard to come by in Australia.Īlso, while I am aware a good tech should do this etc etc, I would prefer to learn and understand this myself so any help you can give me is appreciated. I am confident with doing this myself and I don't have access to a bias probe or bias meter. I would like to rebias my 65 PRRI myself with my multimeter when I change over my 6v6 power tubes.

Bias guitar amp without probe