Anyone else have bad luck with tube amps?

[Inferno]

As the title states, I have bad luck with tube amps. My JTM 45 and 5150 have developed volume issues where while playing at moderate volumes the signal will fade in an out.

Then my Shiva completely goes out on me last week in the middle of practice. Checked the fuses - nothing suspicious - and checked the inside for visual cues as to what may have happened. Nothing. I love how tube amps sound, but this is ridiculous! I'm going to contact Dean Zink soon.

[crusty philtrum]

Re: Anyone else have bad luck with tube amps?

Ok, have to ask the obvious first : have you come to these conclusions, or at least confirmed your suspicions, by plugging your guitar directly into the amps in question using only one cable, one that is known to be good and reliable ?

What i mean is, have you eliminated pedals, multi-effects units, assorted patch leads etc.? And possible even double checked by using a different guitar ?

(not trying to sound like a **** here, but diagnosis of anything involves a series of steps that need to be taken in the correct order, otherwise simple things can be overlooked and cause mayhem and much wasted effort later)

[Inferno]

Re: Anyone else have bad luck with tube amps?

have you come to these conclusions, or at least confirmed your suspicions, by plugging your guitar directly into the amps in question using only one cable, one that is known to be good and reliable ?

I appreciate where you're coming from so no worries. Yes I have tested all the amps with multiple guitar cables. I've been using my (rock solid) 3 month old planet waves cable recently. I've also tried a different speaker cable and a different cab, all to no avail.

The volume swell problems persist no matter what guitar I use, what cable I use, or which cab I use.

Also, I do not typically run any pedals, so that's not an issue.

*When the Shiva worked, it worked perfectly. No volume issues whatsoever and it was played with the same guitar/cab/cable if that helps at all. They all get plugged into the same outlet.

[jcthejester13]

Re: Anyone else have bad luck with tube amps?

Are your tubes in good shape? Any blue or purple shades showing up in the tubes?

[Spudman]

Re: Anyone else have bad luck with tube amps?

Mostly it's tubes wearing out that will be the source of most maintenance for tube amps. It's just the way they work. Sounds like your problems are consistently the same so it's probably time for new tubes. You can do a simple check by rotating tubes into different sockets. If your problem continues do another rotation (assuming you have a 4 power tube amp) until the problem stops. Then you have just determined that one of your power tubes is probably weak. At this point a fresh set of tubes and a re-bias is probably the best thing.

Unless you've been really hard on the amp, or abusive, the whole unit wont do what you describe, especially on multiple different amps. Tubes are the weakest link. Most circuitry is pretty durable.

[Inferno]

Re: Anyone else have bad luck with tube amps?

Are your tubes in good shape? Any blue or purple shades showing up in the tubes?

The tubes on the JTM could use changing. I replaced the tubes on the 5150 about 6 months ago to see if that was the issue, but the volume swells persisted. The Shiva got a retube about 8 months ago, so it should still be good to go.

The tubes appear to be alright. Normal orange glow from all of them. No blue or purple at all.

[jcthejester13]

Re: Anyone else have bad luck with tube amps?

Ever have it on without it hooked up to a cab for any reason?

This sounds like either the transformer or just a cold solder joint to me (since the tubes are all in good shape).

[Inferno]

Re: Anyone else have bad luck with tube amps?

Ever have it on without it hooked up to a cab for any reason?

This sounds like either the transformer or just a cold solder joint to me (since the tubes are all in good shape).

Not to my knowledge. The only one I'm not sure about is the JTM, which stays at my bassist's house hooked up to the cab.

I hope I don't have to replace the transformers. I'm not hard on my amps. They are all warmed up 5-10 minutes before I start playing them and I usually don't go much higher than noon on the volume knobs.

[formula73]

Re: Anyone else have bad luck with tube amps?

I have had this problem with my Cobra for some time, actually. I was told it was the effects loop jack (can't remember which one-the one that turns on the loop when plugged in as the contacts can get iffy from disuse and close/open even with nothing plugged in), so I replaced that and the problem persists. My 2nd set of power tubes and preamp tubes later, STILL, it's a problem. I'm waiting to see what it ends up being for you. A lot of tube amp problems may be related to tubes, yes, but there's a whole lot more in there than just tubes, sockets, and transformers, and a whole hell of a lot of it is cheaper than a new set of tubes, which is what everybody always recommends.

[Inferno]

Re: Anyone else have bad luck with tube amps?

I was told it was the effects loop jack (can't remember which one-the one that turns on the loop when plugged in as the contacts can get iffy from disuse and close/open even with nothing plugged in), so I replaced that and the problem persists. My 2nd set of power tubes and preamp tubes later, STILL...

I feel your pain. My 5150 has an effcts loop, so that is something to look into, but my JTM45 doesn't.

[formula73]

Re: Anyone else have bad luck with tube amps?

I thought it was related to the loop, so (after spending a bunch of $ on tubes to no avail), I replaced both loop jacks and the mix pot as it's got a weird loop that a lot of people don't like, but the problem persists, independent of loop on/off/jumped/level...it's frickin maddening.

[Red_Label]

Re: Anyone else have bad luck with tube amps?

Then my Shiva completely goes out on me last week in the middle of practice. Checked the fuses - nothing suspicious - and checked the inside for visual cues as to what may have happened. Nothing. I love how tube amps sound, but this is ridiculous! I'm going to contact Dean Zink soon.

Have you tried sending an email with your problem, and the steps you've taken to try to rectify it, to Bogner? They've always been pretty good about getting back to me regarding my questions about my XTC (and the EL34 Shiva I owned before that). I say "pretty good" because they're not perfect. For close to that kind of service I'd have to nominate the guys at Traynor (you rock, Guy!).

Anyways... might be worth a shot. Maybe they can give you some ideas to try in order to isolate the issue. I know a guy who ended-up having to send his older model Shiva in to Bogner several months ago for repair. But not before they really tried to give the local amp tech (a really good one) all the info he could use in order to try to fix it locally. Seems like they'd rather help you fix it yourself, or get it fixed locally, than to hassle with shipping back and forth.

Also, are you the original owner? Doesn't Bogner have a lifetime warranty that's good for the original owner? Unfortunately, I'm not the original owner of my XTC. [crosses fingers]

[Inferno]

Re: Anyone else have bad luck with tube amps?

Also, are you the original owner? Doesn't Bogner have a lifetime warranty that's good for the original owner? Unfortunately, I'm not the original owner of my XTC. [crosses fingers]

I bought my Shiva secondhand, so I'm in the same boat. I will try sending them an email to see if they have any ideas before I take it to a tech. Thanks for the idea!

[Inferno]

Re: Anyone else have bad luck with tube amps?

Sorry to bump my own thread, but I may have found out what was wrong with my Shiva. I used an ohmmeter as suggested by Bogner in the manual. It appears that my mains fuse is blown, though you wouldn't know it just by looking at it. I'm going to take a quick trip to ratshack and see if fixes the problem.

[playas]

Re: Anyone else have bad luck with tube amps?

Just a thought but as you´ve described having similar problems with two different amps and you´ve also mentioned that you´re using the same outlet, could it be an electrical issue in your home (or wherever you´re plugging in) causing problems with your amps?