Help. Diezel Amp just quit (update: issue resolved)

  • Thread starter Thread starter Anxiety Serum
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Anxiety Serum said:
Mine is like the picture above. If that is the case do you still recommend not trying the fuse?

Also, is this common, did I do something wrong, or what causes this? Amp is about 1.5 years old. Never leaves home, rarely ever gets cranked past 9 o'clock on the master or the regular volume and I was playing pretty low this morning.
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Like Japetus said - you didn't do anything wrong. Tubes fail. If you replace the fuse and tubes and it dies straight away, then you know it is tech time.

Another trick and I really don't want to be the one to recommend, but you can get a new fuse, remove all the power tubes, remove the guitar signal from input jack, fire it up and if the fuse blows then you are almost guaranteed to have a blown resistor in the power section. That said, I'd really rather someone else weigh in or just take it to a tech. There are some very savvy techy dudes here and lots of Diezel owners too so just hold out a bit for some more advice. Good luck,
 
Was there a burnt smell when the amp shut down?

If not, you most likely did not fry a screen resistor and just had an output tube go south.

The reason why the amp shut down is due to a fuse blowing. They do this to protect the amp.

You’ll need to replace the fuse and output tubes. I put a pic with red box around where the fuse holders for the output tubes are located.

You can safely take a flat head screwdriver to open up the fuse holders and inspect what fuse blew.

It is important to replace the fuse with the exact values Amperage (A) & Voltage (V). They’re rated to blow at those value so you don’t kill your amp in the event of failure.

If you’re not familiar with this bring it to a tech.

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Bossman415 said:
Was there a burnt smell when the amp shut down?

If not, you most likely did not fry a screen resistor and just had an output tube go south.

The reason why the amp shut down is due to a fuse blowing. They do this to protect the amp.

You’ll need to replace the fuse and output tubes. I put a pic with red box around where the fuse holders for the output tubes are located.

You can safely take a flat head screwdriver to open up the fuse holders and inspect what fuse blew.

It is important to replace the fuse with the exact values Amperage (A) & Voltage (V). They’re rated to blow at those value so you don’t kill your amp in the event of failure.

If you’re not familiar with this bring it to a tech.

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Thanks.

No burnt smell.


Thart looks like a VH4. Mine is a VH2..


Is output tube different from power tube or preamp tube or is it the same as one of those two?
 
So is one of these fuses a spare?

Do these tubes look blown or not? Never seen a clean vs blown tube.
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Chubbs said:
The top fuse in your last pic looks like it’s blown.
We’re those two fuses out of the holder by the power cable plug?
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Yep. The top one was closest to the amp in the first pic. Wondering if the second is a backup or its own thing (Can I swap)?

And how do the tubes look?
 
Its blown. Just wondering if the second is a spare or if I need both to be good.
 
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Anxiety Serum said:
Yep. The top one was closest to the amp in the first pic. Wondering if the second is a backup or its own thing (Can I swap)?

And how do the tubes look?
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I can’t really tell by looking at the tubes but yes that second is a spare. Odds are it will blow again, but if it does it’s probably tech time and will need some new tubes.
 
Chubbs said:
I can’t really tell by looking at the tubes but yes that second is a spare. Odds are it will blow again, but if it does it’s probably tech time and will need some new tubes.
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Would you put the new fuse in and try? Or is that risky for the amp.

Would better photos help you tell with the tubes or not?
 
Anxiety Serum said:
Would you put the new fuse in and try? Or is that risky for the amp.

Would better photos help with the tubes or not?
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For the most part you can’t see faults in tubes, you have to test them on a tube tester or open the amp up and poke around with a multimeter.
I would try the spare, they’re quite cheap and you can get more from your tech if the amp needs to go in for service. Maybe film the rear of the amp on startup and see if there is anything out of the ordinary in terms of sound or looks. Just shut the amp off if you hear any humming.
 
The fuse did its job: it saw more voltage than it wanted to send through the amp and it ‘defaulted’ (euphemism for ‘blew’)

By all means, replace with the exact same value fuse - whether fast or slo blo - then power up the amp with the rear panel off and watch each power tube as she powers up. If all 4 glow steady pale orange, you’re good to go. If one fails to glow at all - or goes bright orange to pale red - then that’s your culprit. A matched quad replacement (with re-bias) is 10x better than a mis-matched single in that slot.
 
Definitely the transformateon Amp is dead forever. Time to get a new amp, classic transformateon death, what you described is exactly that.

Just kidding, definitely one of those glowing glass thingamajigs or that little cylindrical thingy that you insert into back of amp, maybe made out of glass and looks like fishing line inside?

Not to worry, I have advanced technical skills and know how.
 
Nothing to say that hasn’t already been said. Look on diezels site to see if there’s a certified repair shop in Raleigh. If not I’d start with google reviews and make phone calls to see who’s comfortable working on it.

Seems tube related. Be prepared to buy a matched quad set of tubes and any additional parts plus labor. A competent tech should have it back up and running in a few hours bench time not including burn in if nothing else severe was damaged in the process.
 
@Anxiety Serum ok so you found the blown fuse.

My 2 cents, replace the fuse and buy a new quad of tubes from TAD, Tube Amp Doctor.

Your old tubes are TAD, so they should have numbers on the base indicating their values.

Those numbers will enable TAD to provide you a matched quad which should run properly with the stock bias point of that amp.

Btw you can check your old power tubes (bigger ones) for signs of heat damage (discolored ink on glass and/or burn marks on the plates aka grey metal part in the tube).

Those are signs of the tube that usually failed. In any event, putting in a new quad is the best remedy when changing out a bad tube.

Also, save your old tubes. If you ever get saavy on how to measure/bias an amp, some of those old spares might still be good and can work in an emergency.
 
Do
Bossman415 said:
@Anxiety Serum ok so you found the blown fuse.

My 2 cents, replace the fuse and buy a new quad of tubes from TAD, Tube Amp Doctor.

Your old tubes are TAD, so they should have numbers on the base indicating their values.

Those numbers will enable TAD to provide you a matched quad which should run properly with the stock bias point of that amp.

Btw you can check your old power tubes (bigger ones) for signs of heat damage (discolored ink on glass and/or burn marks on the plates aka grey metal part in the tube).

Those are signs of the tube that usually failed. In any event, putting in a new quad is the best remedy when changing out a bad tube.

Also, save your old tubes. If you ever get saavy on how to measure/bias an amp, some of those old spares might still be good and can work in an emergency.
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Does Tube amp doctor ship to USA?

The non-local shop I bought the amp from said I should rebias the amp any time you change tubes. Is that correct? I take it your suggestion avoids that?
 
Anxiety Serum said:
Do

Does Tube amp doctor ship to USA?

The non-local shop I bought the amp from said I should rebias the amp any time you change tubes. Is that correct? I take it your suggestion avoids that?
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yes you should re bias when installing a new set of power tubes
 
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