Problems with tube amp

[Lux84]

Having this Randall Diavlo 45 head. At first there was no sound at all. Than i left it alone for few years, cause i played different amps. Now, i bought multimeter, to check out if fuses are blown. It looks like fuses are perfectly ok. Messed up, as i am, i forgot which one is on it's place, so i tried both in 2 different places, and the amp worked well anyway. It magicaly works now, but.. After about 10 minutes of playing, the sound volume droped to a little, and one of the power tubes started to heat as hell, and it glowed to a yellow colour.. to the point, that it started to smell, and i turned the amp down 2 times now because of that. Now that amp is turned off i still hear some crakling in that tube. What is actually going on, if someone could explain me? I hoped there would not be an issue with power tubes, because i have no knowledge to bias them..

 

[devastone]

Re: Problems with tube amp

It sounds like you have a bad tube or a problem in the bias circuit, so, it's probably a visit to a tech either way, especially if you don't know what you are doing on the inside. That's all I have an internet diagnosis, but maybe some others with chime in here shortly.

 

[Lux84]

Re: Problems with tube amp

I hoped that this is just bad fuse, so i bought cheap multimeter to check out, and it turned out, that the power tube is a problem. But i have no car, and no money to do that right now, so i hoped that this is the fuses problem, i could get new fuses and tubes cheap, but i don't know how to bias power tubes.

 

[Gtrjunior]

Problems with tube amp

Yes, it’s time for a retube.
Ime, that volume fluctuation thing is a sign that a tube is faultering. And if it started to redplate...sign #2.

I bought one of these and learned to do it myself. Easy Peasy.

 

[Lux84]

Re: Problems with tube amp

Cannot drive the amp to tech and pay him. If i want this amp to work, i need to learn to bias power tubes by myself.

 

[Gtrjunior]

Re: Problems with tube amp

Cannot drive the amp to tech and pay him. If i want this amp to work, i need to learn to bias power tubes by myself.

You can do it with a multimeter too. I would suggest checking some YouTube videos for that.
There is a little math involved but the actual biasing is easy.
The probe I linked above does most of the math work for you but yes, it isn’t cheap.
I have 4 tube amps so I figured it would be a good investment for me, so I bought it.

 

[Little Pigbacon]

Re: Problems with tube amp

I’m not seeing the probe you linked. Is it the Eurotubes?

 

[Gtrjunior]

Problems with tube amp

I’m not seeing the probe you linked. Is it the Eurotubes?

Strange....it’s gone now. But yes the eurotubes. Here I’ll link it again for anyone that may be interested.

https://www.eurotubes.com/store/pc/Eurotubes-Pro-One-Bias-Probe-for-octal-power-tubes-p144.htm

 

[Little Pigbacon]

Re: Problems with tube amp

I have one of those. It works great. The only thing better would be having two of them.

 

[Gtrjunior]

Re: Problems with tube amp

I have one of those. It works great. The only thing better would be having two of them.

I got tired of having to pay somebody to do it for me so...

 

[Lux84]

Re: Problems with tube amp

The amp worked about 7 months perfectly.. i liked the sound of it. i would experiment with vintage drive pedals on clean channel if it would work.

 

[devastone]

Re: Problems with tube amp

If a power tube is going, the clean channel isn't going to work either, if that is what you are thinking. If it is red plating, the best thing is to quit playing it before the tube totally goes and does more damage. You are better off getting a set of the same tubes that are in it and replacing them, while it would be a good idea to get it biased as soon as you can, just putting good tubes in it will be safer than continuing to play it like it is.

 

[Lux84]

Re: Problems with tube amp

It's just one power tube that heats up too much. Luckily i have amps sims, monitors on computer, recording software so i can continue with playing. Finnancialy i cannot afford repair of a tech, probably not in another 6 months.

 

[Gtrjunior]

Problems with tube amp

Power tubes should be replaced as complete sets. Don’t just replace one tube.

 

[Lux84]

Re: Problems with tube amp

Yeah, someone says it should be replaced seperately, someone as complete sets.. internet is full of different missinformations. better to find my self a qualified teacher, to learn something correctly.

 

[Gtrjunior]

Re: Problems with tube amp

Who said to just replace one tube?
Nobody in this thread that I see.

 

[devastone]

Re: Problems with tube amp

Power tubes get replaced in sets, tubes age with use so you don't want one old tube and one new tube.

 

[dystrust]

Re: Problems with tube amp

Yeah, someone says it should be replaced seperately, someone as complete sets.. internet is full of different missinformations. better to find my self a qualified teacher, to learn something correctly.

Power tubes get replaced in sets, tubes age with use so you don't want one old tube and one new tube.

Preamp tubes can be replaced individually. Power tubes in most amps need to be replaced as a set.

 

[devastone]

Re: Problems with tube amp

Yes, should have been clear on preamp vs power tubes.