Strange rumors from amp after some hundred hours...

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Strange rumors from amp after some hundred hours...

Post by ASAR »

To any of you happened to have a tube amp that started making strange noises like blowings and cracklings, after a certain period of service of the amplifier? :roll:

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Re: Strange rumors from amp after some hundred hours...

Post by GrantB »

Yes. I replaced the tubes and all was well. Have you checked those?
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Re: Strange rumors from amp after some hundred hours...

Post by crowbgood1 »

I have a 70's Laney that does it. It has always been a valve rattling lose in the socket.
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Re: Strange rumors from amp after some hundred hours...

Post by ASAR »

Well, Unique, you did the easiest thing you could. Pity that after a certain period, the problem is as before. Not so, maybe? :wtf:

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Re: Strange rumors from amp after some hundred hours...

Post by GrantB »

Agree ASAR.

Cold solder joint, tranny with a glitch, cap going off?

Have you got a trusted technician who could take a look?

Sell it maybe...?
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Re: Strange rumors from amp after some hundred hours...

Post by crowbgood1 »

Sell it to a 'little old lady'..... maybe not.

Nothing more frustrating than intermittent faults.
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Re: Strange rumors from amp after some hundred hours...

Post by ASAR »

I believe that the technician who can help you is myself, even if I live far away from you. I do not sell anything that would solve the problem. For guitarists who can give me directly their amps, in Italy, I intervene directly to suitably modify the circuitry. In your case, however, I will try to advise you as best I can.
Perhaps you already know that the signal dual triodes typically used in audio (including the amplification of the electric guitar) also have their indicative limits of voltages, currents and power to the electrodes that should never be exceeded (maximum ratings, supplied by manufacturers).
If you go to read this data sheet you will see that list also indicates the maximum voltage that can be applied between the heater and cathodes. If you trust me, I tell you that in the case of heater negative with respect to cathode the maximum permissible voltage is approximately two hundred Volts, and when the heater is positive with respect to the cathode, in practice this voltage is halved (max. 100V).
Failure to comply with these guidelines involves a stress to the tubes and instability for the circuit that after a certain period produces just the strange and "unexplained" noise that some of you, unfortunately, already know.
Sometimes it can be a cold solder made from a inexperienced hand to make noise, but generally the amp affected by this phenomenon have in their circuitry at least one cathode follower. This, typically, is placed just before the tone stack or the circuit of the send / return effects to lower the impedance of the signal.
Before you even think about going to make measurements on your amp, I have to remind you that, if you are not expert enough, the high voltages to which they are subjected their circuits are dangerous and can to endanger human life! It 'best to wear a pair of insulated gloves, even if you think you do not need it! The solution of the problem is "surgical" and if you're not sure where to put your hands and know how to make good welds, you better leave it in the original configuration.
If any of you feel like to try, we can do it together. :winky:

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Re: Strange rumors from amp after some hundred hours...

Post by crowbgood1 »

Oh shit.. and I just put a new retaining clip on the valve.... silly me.
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Re: Strange rumors from amp after some hundred hours...

Post by ASAR »

crowbgood1 wrote:
Nothing more frustrating than intermittent faults.
I fully agree! :wink:
Some times it happens that we go... :crazy:

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Re: Strange rumors from amp after some hundred hours...

Post by willow13 »

so this thread is about spam and not helping you solve a problem with your amp :?: :?: ...or have I read it wrong because it is kinda hard to follow
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Re: Strange rumors from amp after some hundred hours...

Post by Bg »

crowbgood1 wrote:Oh shit.. and I just put a new retaining clip on the valve.... silly me.
You can tighten those sockets with a toothpick as well, makes the world of differece if they've become a little loose.
I'd try that before getting the insulated gloves out
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Re: Strange rumors from amp after some hundred hours...

Post by ASAR »

If you think this thread is spam, or that to solve the problem that UNIQUE seems to have understood is sufficient tighten or replace any component, go ahead as you want. No problem, for me. I can also spend my free time in other ways.

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Re: Strange rumors from amp after some hundred hours...

Post by willow13 »

ASAR wrote:If you think this thread is spam, or that to solve the problem that UNIQUE seems to have understood is sufficient tighten or replace any component
seems to me he was offering YOU suggestions on how to fix YOUR amp. If you are offering tips on how to fix then try and word it that way and not as a question (again maybe I am the only one who took it that way :eh: )
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Re: Strange rumors from amp after some hundred hours...

Post by Vince »

willow13 wrote:so this thread is about spam and not helping you solve a problem with your amp :?: :?: ...or have I read it wrong because it is kinda hard to follow
Yeah, a question mark ("?") at the end of the thread title would have made things clearer.

Not sure that it's spam: I think it's unlikely that anyone here would send an amp all the way to Italy to be fixed. ;)
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Re: Strange rumors from amp after some hundred hours...

Post by ASAR »

You're right, Willow, it's just like you said. I, however, wanted to say to UNIQUE that the solution of replacing tubes solves the problem only temporarily. After I have started to expose the problem technically, at least in the premises. I'm sorry for my bad English.
I do not have an amplifier with this problem, but I'd like to help those who have to be able to solve, since I know the solution.
I hope I explained, now.

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