#1
Ok, So I had volume cutting out after a while on my 69 bassman. I figured it was the power tubes as they were rather old, so i changed them, and the pre amp. Turn on the amp, and there is no sound, the tubes are glowing, but there is no sound. When I turn up the volume really loud and play a note, you can hear sound but it is coming FROM the power tubes? Also, they glowed much more brightly when played.. I promply turned it off.

What could this be? Please help..
#2
Check the simple things. Is it a head? If so be sure it is connected to the cab and that you are matching ohms. Other than that I imagine it would be the output transformer. If the tubes are good and the amp turns on but there is no sound then you probably blew the OT.
#3
Quote by Tyler.Allain
Check the simple things. Is it a head? If so be sure it is connected to the cab and that you are matching ohms. Other than that I imagine it would be the output transformer. If the tubes are good and the amp turns on but there is no sound then you probably blew the OT.


Yeah its defintly connected fine. There is no sound from the speaker, not even a hum. It was working fine, then a couple times the volume would cut out after being on for a certain amount of time. I heard this could be solder joints heating up and un soldernig. Is that possible? I'm praying to god its not an ot. Like I said the power tubes are making noise which is weird, but maybe normal..
#5
Quote by stykerwolf
changing colours how? Red or wierd purple/oil effect?

Nope, just like a brighter orange. That might be normal idk. They are brand new, so they are glowing brighter than the 40 year old ones before..

I'm really hoping its not the ot....
#6
Also, I forgot, that ocasionally, a sound would happen that was similar to plugging in a guitar. A popping sound of sorts.
#8
Quote by AcousticMirror
you should take it to a tech and get it checked out and rebiased.

That was the plan, i ordered new power tubes and everything, figuring the fact that it cut out after a certain amount of playing was just the power tubes. But then I put them in, and it's no different. Do you think that it could've been the old solder joints getting too hot and thats why it cut out, and now one is just completely unsoldered? I'm gonna take it to a tech tomorow, just hoping its something not so bad
#9
could be any number of things.

usually need to rebias after you put new tubes in anyway.
Prs se Holcomb is the answer