Very loud amp is now attenuated

[newguitarsmell]

Hi I have a tube amp for my keyboard. It’s usually super loud but today when I plugged it in at a gig it was like I had dropped the wattage somehow. I could play through it, but it was more bedroom levels - bad for a live gig.
Before I take it to the repair shop, anyone have any ideas?
I plan to try swapping out the preamp tubes but how can I tell if my PT is failing?

[kagliostro]

May be if you add some info like amp brand and model (and a schematic if you have one), it will be easier to try to give you help


Franco

[newguitarsmell]

It was a one off hand built of vintage parts. I don’t have a schematic. I was just curious in general.

[JPK]

It's just a loose wire. I'm 100% certain based on your info. 

[newguitarsmell]

You guys can be so helpful..

[shampeon]

It's almost never a transformer failing. There are a lot of reasons (so many!) why a tube amp might have low output, and none of them can be diagnosed with as little info is in this thread, so I dunno man.

[kagliostro]

Is like someone ask for his car, the car didn't reach the usual velocity but we don't know if the engine is electric, diesel, gasoline, if it has an automatic or hand actioned, if the tyres are intact or punctured and so on


Franco

[Merlin]

A failed OT will normally produce no output or very quite, thin and distorted output, not bedroom levels.