5E3 works after 1 hour playing

[Leevi]

I got a question regarding 5E3. There is some kind of power loss and
the amp starts work about one hour playing. Any ideas where to start to troubleshoot?
Power tubes have been changed.
/Leevi

[tubenit]

When you first turn the amp on .................. take voltages.   After an hr of playing when the volume is "right"  ............. take voltages again.   Any difference?

Look for bad solder joints.  Triple and quadruple check every connection and solder joint.

My guess is something is expanding from heat and improving contact allowing better power.

with respect, Tubenit

[archaos]

Yep, +1, & perhaps particularly bad solder joints as regards the speaker plugs if you used flat plugs.

[Leevi]

Unfortunately the amp is not by me right now.
The amp is first very bass sounding and needs more more volume than normally.

My guess is something is expanding from heat and improving contact allowing better power.

I was thinking if a coupling capacitor could be the reason?

/Leevi

[Leevi]

perhaps particularly bad solder joints as regards the speaker plugs if you used flat plugs

I got the amp and tested it but I didn't get problem repeated  any more.
I found a partly open flat speaker plug which could have caused the problem.
/Leevi

[archaos]

I got the amp and tested it but I didn't get problem repeated  any more.
I found a partly open flat speaker plug which could have caused the problem.
/Leevi

Cool if you found the culprit.