anyone with knowledge on amps and tubes please help me
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Posted on Oct 11, 2008 06:03 pm
End of Fall
Mikey Spencer
Member Since: Apr 26, 2007
i know i posted this issue already but i was kinda vauge and i was posting about it on harmony central and i wrote really in depth on how this happened so i figured i'd post it here....
okay, so i got a valve jr.... super happy with it, surprised with the volume of it. I gigged with it a few times with it at about 1 o'clock. One morning after i had played it the night before and i turned it on to start playing and i realized it look longer than normal to heat up. When it heated up it played like normal until after a few minutes the sound just faded out. I turned it back on a few times and it would take a long time but eventually it would play but only a short amount of time before fading out.... then finaly one day i tried turning it on and i got power but i never got any sound and haven't since.
I've been told that this could be cause of a bad power tube, pre amp tube, or like a bad fuse or some other stuff. idk a ton about amps and i haven't gotten any good advice yet but im hoping some people on here can figure this out.
If it is a tube change what would be some good options? I don't want any earliar breakup than the stock tubes gave. I liked where it broke up just maybe if it was a bit warmer.
- thank you so much
also, if it's a tube change can anyone give me good instructions or direct me to a good tutorial.
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Dematrixhttp://www.reverbnation.com/2ndgMember
Since: Nov 27, 2007
Oct 11, 2008 08:06 pm changin the tubes is simple. i awlways use a soft glove or a rag so you dont touch the glass, im sure it doesnt really matter a great deal, but i dont want any reason for it to get oil or moisture on it and then crack.
just pull out the old and in with the new.
tis the case with mine anyway. some amps have a little lock down thingy over the tube, so you should be able to just flick that back and remove tube.
just jiggle it out slowly. some are tight.
are your head and box ohms matched? If not, what are you running them both at ???
TadpuiI am not a crook's headMember
Since: Mar 14, 2003
Oct 12, 2008 03:25 pm How old is the amp? And how often do you play it loud?
Power tube outage/malfunction isn't out of the question and its a relatively cheap fix to swap it out. Heck, with those Valve Jr. amps, its usually worth swapping out the power tube with something a bit more warm and fuzzy than the stock tube anyways.
It's definitely not a fuse or else you'd get no sound whatsoever. So that points to tubes or power transformer. I'd imagine that a power transformer problem would result in no sound as well, so I'd say that the prime suspect (as far as user-serviceable parts go anyways) would be power or preamp tubes.
If a power tube or preamp tube swap doesn't cure the ailment, then take it to a trustworthy amp tech. With tube amps, you don't want to go poking around in there or else you could get a lethal dose of elecricity, even when the amp is unplugged.
Dematrixhttp://www.reverbnation.com/2ndgMember
Since: Nov 27, 2007
Oct 12, 2008 09:08 pm oh, the ol electricity thing eh? i agree Tad, im living testament to the fact that your tendons can only take so much electricity before they start shrinking.
I have had about 3 or 4 really good boots in my life and it has repercssions.
i was thinking to check the ohms matching asap just to make sure you havent fried it as well.
pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Oct 20, 2008 08:23 am oops, missed this thread.
in tube amps, there are capacitors, electrolytic type, that smooth out the DC that's created from AC.
These caps can go bad over time, and start to give out. It sounds more like this than a tube, though I wouldn't rule out the tubes either.
Replacing E-Caps (or filter caps, as they're sometimes called) is a soldering job, as you have to unsolder the old ones, and solder the new ones in.
Like Tad says, don't poke around in tube amps unless you know how to make them safe. Hundreds of volts can lie in wait to discharge, and kill you if you are the path to ground.
www.tedweber.com has a page to look for tube amp techs:
www.webervst.com/techreg/techreg.htm
Good luck.
Oct 21, 2008 05:08 am i fixed it the other day. the fuse had just slipped off. after the HARD time i had of taking off the back panel (i had to pry it of with a screwdriver!) i just grabbed it and popped it back into place and it was working. i was pretty darn proud of myself.
