Ampeg VT-60 help

[ampegguitarplayer]

"According to the technical notes on the schematic: "with amp in pentode mode and no signal applied, adjust P14 (bias control) for 0.05V +/- .01V between TP1 and TP2"."

okay, i know the pentode mode. i just dont know the "0.05V +/- .01V between TP1 and TP2" part.

can anyone help. this amp is smoking when i turn it on, and i need it. ive bought new tubes, the right tubes. i know its not the speaker, and if the new tubes in it arent helping, the problem must be the caps.

[teemuk]

TP = "Test Point", so the amp should have test points labelled TP1 and TP2 somewhere. I don?t know about the actual physical location of these but the schematic should at least show the location circuit wise. For example, in VT-120 these are located in the cathode circuit of the output tubes. I?m pretty sure the amp board has TP1 and TP2 printed in somewhere and convenient spots for probing just beside the prints. Plug the meter's probe ends to these spots and adjust the bias so that the meter shows the said measure.

[ampegguitarplayer]

Originally Posted by teemuk

TP = "Test Point", so the amp should have test points labelled TP1 and TP2 somewhere. I don?t know about the actual physical location of these but the schematic should at least show the location circuit wise. For example, in VT-120 these are located in the cathode circuit of the output tubes. I?m pretty sure the amp board has TP1 and TP2 printed in somewhere and convenient spots for probing just beside the prints. Plug the meter's probe ends to these spots and adjust the bias so that the meter shows the said measure.

okay, simple enough.


so here goes some very stupid tube noob questions...

do the preamp tube need to be biased? are they biased with the power tubes as well?


i have no idea what i am doing, as i am going to take my amp to a specialist. but i would still like to know.

[teemuk]

http://www.aikenamps.com/WhatIsBiasing.htm