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Tube amp help

Posted: Fri Nov 10, 2017 5:54 pm
by Jim.h
Hello all!

Ive been playing tube amps for years and have never had any problems at all! so this is a first.

When im playing my orange rockerverb, it has sudden drops in volume. just for a moment or two and then comes back to normal.

Could this be a power tube problem?

I live in hamilton. Was thinking of taking it into the rock shop for them to have a look (worry about their competence) I know the great John Gilmour is retired.

Does any one have any suggestions on what I can do?

Sure google can help, but where is the fun in that?

Cheers guys!

Re: Tube amp help

Posted: Fri Nov 10, 2017 6:04 pm
by sizzlingbadger
Could be any tube, get a known good tube of each type and test the amp by replacing them with the good tube one at a time to see if it helps. I'd start with the power tubes as they are more likely to cause this issue.

Re: Tube amp help

Posted: Fri Nov 10, 2017 6:19 pm
by chur
My Jet City did this when one of the EL84's in the power section started red plating. You could see this watching the tube when the volume was dropping as it glowed. Guess you could swap tubes, or find someone with a tube tester.

Re: Tube amp help

Posted: Fri Nov 10, 2017 6:23 pm
by Olderama
Yep swapping tubes is a good start :)

Re: Tube amp help

Posted: Fri Nov 10, 2017 7:14 pm
by olegmcnoleg
I'd start with the power tubes, they tend to be the ones to go...(especially EL84s, from experience). You will need to replace them in balanced pairs of course, or find a replacement with the same bias as the bad one.

Re: Tube amp help

Posted: Fri Nov 10, 2017 7:35 pm
by AiRdAd
I'm not sure if it's been mentioned in this thread before, but I'd start with the tubes...

Re: Tube amp help

Posted: Fri Nov 10, 2017 7:40 pm
by GrantB
Not sure if John is retired...but I haven't seen him in a few weeks.

Check the power tubes...

But in seriousness, could it be an input not touching properly briefly? A bit of electric spray in there?

Re: Tube amp help

Posted: Fri Nov 10, 2017 7:52 pm
by Bg
I'd start by putting it in the bin and getting a katana.

Re: Tube amp help

Posted: Fri Nov 10, 2017 11:30 pm
by Single coil
My amp was cured of this by finding the dodgy patch cable and replacing it.

Re: Tube amp help

Posted: Sat Nov 11, 2017 3:16 am
by Molly
You could try playing more slowly. :-)

Re: Tube amp help

Posted: Sat Nov 11, 2017 3:43 am
by higainer
Had the same issue, faulty power tube.

Re: Tube amp help

Posted: Sat Nov 11, 2017 6:09 am
by Jim.h
thanks guys! BG... not so much lol

Im thinking its a power tube too.

Re: Tube amp help

Posted: Sat Nov 11, 2017 10:48 pm
by Single coil
If it’s blue and cloudy then yeahp!

Re: Tube amp help

Posted: Sun Dec 10, 2017 10:46 am
by tubeswell
Loss of output power is often a symptom of failing output tubes. Output tubes wear out faster than preamp tubes and need replacing more often. Some output tube types (e.g. EL84 and similar miniature envelope pentodes) wear out faster than others.

Re: Tube amp help

Posted: Sun Dec 10, 2017 11:17 am
by Thewilltopowerrock
Check the tubes, Jim.