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Hoffman Amps Forum image Author Topic: A new fault/sound I had never seen before  (Read 1818 times)

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Offline Planobilly

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A new fault/sound I had never seen before
« on: December 12, 2016, 04:00:08 pm »
Hi Guys,

I just repaired a Fender Blues Deville 212. The drive channel made a sound like a small motorcycle and got louder as the master volume was turned up. I had never seen a amp act just like that. I assumed the issue was a cap somewhere and that was a correct assumption. I found a defective 22uf filter cap and problem solved.

Motorboating I have listen to but motorcycling was a new one on me...lol

Anyone have any idea how a bad cap actually causes the sort of noise/oscillation?

Cheers,

Billy
Between fishing, flying, and fooling around with guitar amps, somehow 70 years got behind me. Shorter of breath and one day closer to death as the song goes.

Offline HotBluePlates

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Re: A new fault/sound I had never seen before
« Reply #1 on: December 12, 2016, 05:14:43 pm »
So you had motorboating which was a few-Hz higher in frequency than what you usually hear...  Mechanism will be exactly the same.

The ear tells you there is a big difference between setting your trem to minimum speed (maybe 4-6Hz) and maximum (maybe 10-12Hz), but that depends on your perspective (doesn't look like a lot when just talking numbers).

Offline Planobilly

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Re: A new fault/sound I had never seen before
« Reply #2 on: December 12, 2016, 06:12:46 pm »
Thanks for the feedback. No pun intended..lol

Just a strange sound I had just never experienced before.

Cheers,

Billy
Between fishing, flying, and fooling around with guitar amps, somehow 70 years got behind me. Shorter of breath and one day closer to death as the song goes.

 


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