need help with liverpool to 36w tmb conversion
Posted: Mon 03/01/10 12:45 pm
hello everyone- i am new to this forum, and i would appreciate any input on a problem i'm having with my attempt to convert my TW liverpool to a 36w TMB. I am only using one channel (TMB high input) through the CF tone stack, and then through the liverpool's power section. I am only getting very quiet amount of sound with both the volume and master dimed. I am getting audible pops when I test the plates of the EL84s and the PI, but no sound from V1 or V2. I used the preamp board from the liverpool and ran the 36w pre on it. My pots are, from left to right on the pic, vol 1M, treb 250K, mid 25K, bass 1M, and MV 1M. I checked for cold solder joints, bad resistors, traced the circuit as best I could. I checked preamp tubes with another amp and they are all good. I am also using the B+ volages from the liverpool, which are a little different than the 36w. I will include my voltage chart and a few pics of the preamp wiring if anyone would be willing to check my work. Thanks again for any input!
V1 p1-137, p2-input, p3 1.05. Other triode not used.
V2 p1- 134, p2- vol input, p3- 1.00
p6- 214, p7- 134, pin 8- 134
V3/PI p1,6- 246, pin2,7- 199, pin3,8- 215
*can't figure out why the grids and cathodes aren't correct
EL84s- plate 337
screen 315
cathode 18.8
bias resistors 150 ohms each side to bias approx 12w each
V1 p1-137, p2-input, p3 1.05. Other triode not used.
V2 p1- 134, p2- vol input, p3- 1.00
p6- 214, p7- 134, pin 8- 134
V3/PI p1,6- 246, pin2,7- 199, pin3,8- 215
*can't figure out why the grids and cathodes aren't correct
EL84s- plate 337
screen 315
cathode 18.8
bias resistors 150 ohms each side to bias approx 12w each