Anyone else have bad luck with tube amps?

Re: Anyone else have bad luck with tube amps?

Red_Label said:
Well... did the fuse fix the Shiva? Enquiring minds want to know! :D
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The fuse was the problem! I'm going to try to upload a picture of the blown fuse. It's pretty difficult to tell that anything's wrong with it. :reporter:
 
Re: Anyone else have bad luck with tube amps?

tube amps for me seem to be the most consistent pieces of equipment that I own.
 
Re: Anyone else have bad luck with tube amps?

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The slight cloudiness in the first picture is actually a small amount of residue inside the fuse from when it blew.
 
Re: Anyone else have bad luck with tube amps?

Good to know it wasn't a blown transformer or something incredibly dire and expensive.

So, I guess the question remains; what's the issue with the other amps and the volume fades? Fuses going bad too, or something worse? \=
 
Re: Anyone else have bad luck with tube amps?

I'll check my fuses in the morning, but I've been having the problem for quite some time, at least a year or so. I'm doubtful.
 
Re: Anyone else have bad luck with tube amps?

sufferinrewind said:
Good to know it wasn't a blown transformer or something incredibly dire and expensive.

So, I guess the question remains; what's the issue with the other amps and the volume fades? Fuses going bad too, or something worse? \=
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Very true - I really didn't want to have to buy a new transformer or two!

The volume issue is still a problem with the other two amps. I think a trip to the tech is the only real way to find out what's up with them. I'm a novice when it comes to electronics, so diagnosing what's causing the volume to swell is way beyond my capabilities.

To formula73: The fuse was only a problem in my Shiva. It wouldn't turn on at all until I replaced it. I don't think the volume problem has to do with the fuses at all, but I'll just have to wait to take them in.
 
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Re: Anyone else have bad luck with tube amps?

Screw it. I've got a couple old RCA 12ax7s floating around. I'm going to start swapping preamp tubes.
 
Re: Anyone else have bad luck with tube amps?

Before going to a tech I'd try changing the tubes for ones known to work.
 
Re: Anyone else have bad luck with tube amps?

Inferno said:
The fuse was the problem! I'm going to try to upload a picture of the blown fuse. It's pretty difficult to tell that anything's wrong with it. :reporter:
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Great to hear man! Always nice when it's something little/easy/cheap like that. Too bad cars aren't usually so easy and cheap to fix!
 
Re: Anyone else have bad luck with tube amps?

For the record, tubes glowing blue doesn't mean they are bad. Most good tubes will have the blue glow, actually. NOS dudes can back this up.

Purple or pink is baaaaad, and means you need to replace them, soon.

Red glow on/through the plate structure is very bad, and might do damage to your amp. If the tubes are new-ish this means you're probably biased too hot. Once they go red you'll have to replace them though.
 
Re: Anyone else have bad luck with tube amps?

Couple of thoughts.

First - power tubes wear out, especially if they're biased hot. Preamp tubes can last virtually forever provided you don't drop the amp when they're hot, etc. I'm not saying preamp tubes don't ever go bad. It's just much more likely that a problem is the power tubes.

Second - fuses don't blow just for the fun of it. Fuses are put in electrical circuits to protect the circuit. Something shorted or spiked or whatever to make that fuse blow. Please make sure you replace the fuse with the correct value and if it blows again, take the amp to a tech.

Third - do the other 2 amps have PCB mounted input jacks? Sometimes one (or more) of the "legs" on the jack breaks its solder joint on the board but still has decent mechanical contact most of the time. This can easily happen even if you're careful about not yanking on your guitar cord. Heck, dirty jack contacts can cause intermittent volume drops.

Hope this helps,

Chip
 
Re: Anyone else have bad luck with tube amps?

My Cobra is PTP. It's got PCBs but everything is flying leads. My volume drops/comes back on all channels at all volumes. Gain stays consistent. I read that the V1 is shared on all channels, but if that were bad, wouldn't gain be the problem, not volume? How about the PI? I know that changing to a lower gain PI in my M1000, like a at7 or au7 dropped the input level to the power section. Does that make sense to anybody but me?
 
Re: Anyone else have bad luck with tube amps?

Fresh_Start said:
Couple of thoughts.
Third - do the other 2 amps have PCB mounted input jacks? Sometimes one (or more) of the "legs" on the jack breaks its solder joint on the board but still has decent mechanical contact most of the time. This can easily happen even if you're careful about not yanking on your guitar cord. Heck, dirty jack contacts can cause intermittent volume drops.
Chip
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The JTM 45 is ptp and the 5150 is pcb, so that could be a possibility with the later. I'm going to buy some new tubes for the JTM and see if that fixes the problem. I've already replaced the tubes in the 5150 which didn't solve its volume issues.
 
Re: Anyone else have bad luck with tube amps?

Just throwing this out there: my PI wasn't the problem, so it's got to be a connection somewhere. I wish there were more Cobras out there so somebody could share any similar experiences.
 
Re: Anyone else have bad luck with tube amps?

The Effects loops on Peavey Amps are notorious for causing issues such as this.

Try putting a 1' cable in the loop and see if the problem goes away.

if you retubed the 5150 6 months ago, I find it hard to believe that they could wear out that fast. Those amps are biased extremely cold, so they get a much longer tube life I believe!
 
Re: Anyone else have bad luck with tube amps?

Warheart said:
The Effects loops on Peavey Amps are notorious for causing issues such as this.

Try putting a 1' cable in the loop and see if the problem goes away.

if you retubed the 5150 6 months ago, I find it hard to believe that they could wear out that fast. Those amps are biased extremely cold, so they get a much longer tube life I believe!
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Thanks for the input Warheart. The fact that the issue was present before and after the tube swap leads me to believe that the 5150's problem isn't the tubes. I did a complete re-tube too, so unless I got some bad tubes then it has to be something else.

I've heard that effect loops can cause volume issues, so I'll try running a cable in the loop when I jam later and see if that helps.
 
Re: Anyone else have bad luck with tube amps?

Bad luck with tube amps? Noupe, we are just fine. I do have issues with speaker cables and certain power adapters.
 
Re: Anyone else have bad luck with tube amps?

Inferno said:
Thanks for the input Warheart. The fact that the issue was present before and after the tube swap leads me to believe that the 5150's problem isn't the tubes. I did a complete re-tube too, so unless I got some bad tubes then it has to be something else.
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I had a problem with my earlier amp. It had some transformer problems before and new tubes didn't help so I thought it was broken. I took it to a tech. Turns out one of the new tubes was bad. Learned my lesson right then and there.
 
Re: Anyone else have bad luck with tube amps?

You guys might want to have the power and wiring in your houses checked. It sounds to me like you guys might have an incoming voltage problem. It your voltage drops or sags, your volume is going to drop with it. My amps will do it here, if I'm playing and my wife starts doing laundry, when the drier kicks on, my volume drops. My room and the laundry room are on the same circuit breaker. Now if I switch over to the rack while the drier is running, it doesn't do it. It only seems to affect the tube powered stuff.

I would go around and unplug or turn off everything that's on the same circuit your amps are plugged into and see if that helps. If it does, you need to look into getting a power regulator. I think Furman makes a good one that's reasonable priced. A constantly sagging and spiking AC line can cause fuses to blow and be really hard on your amps.
 
Re: Anyone else have bad luck with tube amps?

I've had this problem in 2 houses and more than one practice space, but I'll get it figured out. What really kills me is that this is probably the best amp I'll ever get and I absolutely love the hard, biting tone, but right now, I can't trust it.

BTW: sorry for the thread hijack, man. I know you posted looking for help for yours and I just glommed on...
 
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