Faulty practice amp

Amps, Cabs, Speakers, etc
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laurie
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Re: Faulty practice amp

Post by laurie » Mon Mar 06, 2023 2:15 pm

If it is coming and going based on physical manipulation, I would take a non-conductive "stick" and tap all through the wiring and everything connected to it (capacitors, fuse, transformer) to find the source.

The ideal "stick" is non-conductive (IMPORTANT!) and has some weight. A plastic chop-stick or knitting needle is perfect.

If something does change with vigorous tapping, narrow the source of the problem down by reducing the force of the tapping and finding exactly which thing is the problem.

If nothing changes with vigorous tapping of everything, you will have proved that the fault isn't mechanical. If it isn't mechanical, let us know and we can continue the search.

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Gasgano
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Re: Faulty practice amp

Post by Gasgano » Mon Mar 13, 2023 6:30 pm

OK. So... I've disconnected the amp for a few days. Plugged it back in:

The noise was gone. Figured it had to be a capacitor. left it plugged for a few days. Still no noise. Placed the amp back where it should be (but with no screws). Still no noise. Screwed everything back together. Still no noise. Hmm... Maybe it's not a capacitor afterall.

WIll continue monitoring it without moving it to see if the problem comes back.

If it doesn't, I think I might have solved it for good.

If it does, I think it might be a capacitor. Will keep you posted.
"People who are late are usually in a better mood than the people waiting for them to show up."

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laurie
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Re: Faulty practice amp

Post by laurie » Mon Mar 13, 2023 9:41 pm

Ohhh... fixes like that are annoying (to me!) when there is no clearly visible root-cause.

Hoping that it is cured!!

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Gasgano
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Re: Faulty practice amp

Post by Gasgano » Tue Mar 14, 2023 11:51 am

Agreed 100%. Annoys me as well. What reassures me that it might be that marette that I replaced is that :

- The noise went away when I fiddled with wiring. a component failing would have not showed that behaviour.
- It was pretty easy to disconnect the first time, implying there was some slack there already.
- The last manipulation I made was disconnect the marette again and tight it again.

Also, when (carefully) disconnecting the marette when power is on, the moment the wires are "not quite together", the hum came back.

Was still working fine yesterday. No noise.
"People who are late are usually in a better mood than the people waiting for them to show up."

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