Measuring B+ on 12AX7 - before or after plate load resistor?

4/24/2000 6:54 PM

beto

Measuring B+ on 12AX7 - before or after plate load resistor? I purchased an old Supro amp that does not work well. I want to fix it up and in the process learn about tube amps. First, I am simply measuring voltages and currents at lots of different points and recording all my findings.     Q1: I measured voltage from pin6 to ground on my first 12AX7. It showed 85 volts DC. Then I measured on the other side of the plate load resister and it showed 240 volts DC. Am I doing this right? Which one is the "B+" voltage?   Thanks