Laney LC50 sounds muffled/distorted

[opauly]

Hello! My LC50 combo sounds awful. In any setting the output is distorted, with very low output and muffled-like sound. I already tested with a tube tester and a multimeter:

- Tubes
- Grid and cathode resistors
- Speaker
- Bias voltage

And some other tests, but all components seem to be fine. Any hint of what could be causing this?

 

[JMFahey]

Try the speaker with another amp and yours with another speaker.

Try feeding clean audio into loop return or power amp in, if available,also send preamp signal to another amp.
So you split the combo in 3 (pre/power/speaker) to at least isolate the bad area, then we can concentrate on it.

That said, you *might* have a dead/shorted OT 🙁 , but we´ll cross that bridge when we get there.

 

[opauly]

Try the speaker with another amp and yours with another speaker.

Try feeding clean audio into loop return or power amp in, if available,also send preamp signal to another amp.
So you split the combo in 3 (pre/power/speaker) to at least isolate the bad area, then we can concentrate on it.

That said, you *might* have a dead/shorted OT 🙁 , but we´ll cross that bridge when we get there.

Thanks for the reply. So you say to connect the amp as the picture?

LC50 Manual

 

[opauly]

I think I got to the problem. After bypassing the effects loop, the amp returned to normal conditions, so the issue was probably dirty jacks. I cleaned the jacks and maybe need to replace them. Thanks for the help JMFahey!