Bad tube or bad cap?

[Colas LeGrippa]

Hi my friends, got an amp here that works fine but from time to time gives a loud fart ( just like me  ).  Are there more chances that the sound comes from a bad tube or a bad cap? The chopstick method did not reveal nothing.


Thanks


Colas

[shooter]

bad tube or a bad cap

try monitoring voltage over time, maybe hours, at idle.  dropping Volts "should" indicate a leaky cap. swap tubes and see if it farts

[Colas LeGrippa]

Q: bad caps or bad tubes?
A: Bad tubes.


I was surprised to realize that old tubes could fart from time to time and still sound good. I put the beast on test for 12 hours while working and swapped the tubes for new ones. That was the easiest move to make before replacing the power caps. I didn't have to change the caps, farting has stopped with new tubes. The old tubes were drawing approx. the same current as the new ones. What happened in them? Stomach problem ?


Colas LeGrippa

[shooter]

I was surprised to realize that old tubes

I talked with a musician after his set, told him I thought his tubes were about dead, he smiled, said he knew, then told me there is no sound better than a twin with dying tubes.  I did agree he had a great set, although the tech in me was twitchin

[Tony Bones]

It might have been dirty contacts somewhere, probably on the tube sockets . Pulling out the old tubes and pushing in the new ones cleaned the contacts enough to stop the unpleasant noises.

Just for kicks, try putting the old tubes back in.

[Colas LeGrippa]

Just for kicks, tubes were bad.


Have a good day!


Colas

[Tony Bones]

Sorry. Didn't mean to offend.  :)

[John]

You can't offend Colas, he's too busy kissing his wife. 

[Willabe]

You can't offend Colas, he's too busy kissing his wife. 

 

[Colas LeGrippa]

how did you know about my wife ????

[Colas LeGrippa]

she told tou you everything about me, didn't she ?

[Colas LeGrippa]

oops sorry for the ''tou'' ( it is not even a french word....)

[PRR]

> how did you know about my wife ????

She tells us every night. 

> oops sorry for the ''tou''

Just FYI: there is a "Modify" icon above and/or below your posts. You can fix your own words before anybody sees them, or even later.

Do be careful. Some browsers jump to the bottom of the page "New message" instead of the Modify Message box.

[Colas LeGrippa]

OMG, my wife won't get any kiss from me for a while....