1980 twin reverb trouble shoot

[ampmike]

Hey,
Can anyone help me out,I recaped this amp,normal channel is half as loud as reverb channel,reverb channel the treble and base do not sound any diff on 1 or 10 they have no effect on the tone.i checked all the tubes anyone have my next step to fix this beast. THANX MJC

[darrellcheng]

Hello and welcome to the forum. I don't know how much experience you have but you better be careful inside of an amp, know the safety precautions first. Can you explain what you've already done to the amp? Is it a 100W or 135W? Make sure you get the schematic first at schematicheaven.com
You can start by making sure everything is connected, use a meter to test continuity. Isolate the problem between the power and preamp section. Give us some more info on the amp, has it been modded?

[ampmike]

135 ultrlinear tran

Thank you,
Well i recaped the amp ,replaced all power tubes,found 1 bad pot, replaced it and its working ok .The normal channel is not as loud as the reverb channel. The hum is a little better.My experience is entry level i built one amp at chicago school of guitar.I just trying to get more experience now.Should i keep replacing caps one the normal side of the board to get the vol on that channel
to be louder.
Your advice would be greatly appreciated.

[darrellcheng]

Try swapping a good tube with the one in v1. Can u make sure the wiring and values is correct, compare it to the schematic. No need to change the tone caps unless you see that they are bulging. the e-lytics must be changed though. some pics of the guts would be nice. check shorting jacks at the input, and resistors too!

[mac1amps]

Be aware of the fact that the "Vibrato" channel has a bit more gain to it than the "Normal" (non-reverb) channel. It's completely normal, for a "Normal" channel to sound much less "lively" than the "Vibrato" channel (primarily due to the added gain of the post-spring "pick-up" stage of the reverb, which affects the gain even when the reverb is not in use).

[tboy]

Did the symptoms exist before you started working on the amp, or did they appear afterwards?

Which pot did you replace?

Which capacitors did you replace (B+ filters, bias filters, cathode bypass, interstage coupling, every cap in the amp)?