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Topic: Potentiometers |
David Nugent
From:
Gum Spring, Va.
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Posted 14 Oct 2016 11:11 am |
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| Need to replace both volume control pots in a tube amp, what value are these units normally (500K)? |
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Bill Sinclair
From:
Waynesboro, PA, USA
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Posted 14 Oct 2016 12:13 pm
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| What make and model? I've seen volume pots at 100K, 250K, 500K or 1Meg depending on the design. |
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David Nugent
From:
Gum Spring, Va.
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Posted 14 Oct 2016 4:31 pm
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| Fox Vintage Amp. Two volume pots are very scratchy, sprayed both with Deoxit and helped quite a bit but did not completely eliminate the issue. |
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J Fletcher
From:
London,Ont,Canada
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Posted 14 Oct 2016 4:46 pm
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| you should check that there isn't any DC voltage on those pots. Even a little will make them scratchy. Seems odd they would both be scratchy. Could be a leaky coupling cap. |
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Steven Paris
From:
Los Angeles
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David Nugent
From:
Gum Spring, Va.
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Posted 15 Oct 2016 4:19 am
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| If possible, may just send it to Ken for a total check up. The unit sits idle for extended periods and seems to have developed this problem recently. Thanks to all for the replies...Steven P; The link to the site that you provided seems to be down at the moment. |
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Steven Paris
From:
Los Angeles
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 15 Oct 2016 6:24 am
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| David Nugent wrote: |
| Fox Vintage Amp. Two volume pots are very scratchy, sprayed both with Deoxit and helped quite a bit but did not completely eliminate the issue. |
Did you spray them inside (from the back)? Spraying just into the shaft on the front often does very little to clean the resistor element. |
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David Nugent
From:
Gum Spring, Va.
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Posted 15 Oct 2016 9:23 am
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| Donny..Yes, removed the back panel and sprayed 'Deoxit' cleaner first then the lube directly into the pots rotating the knob as I did so. Definitely an improvement but still far to noisy for my liking. Have contacted Ken and he has agreed to remedy the problem...Thanks again. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 21 Oct 2016 1:44 pm
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They may be too far gone then, Danny. Usually, I'll spray the back heavily (if it's open, or remove the back cover if it isn't) and then rotate the pot quickly from stop to stop about 25-30 times. Normally, they don't "wear out" in an amp, but they get corrosion and dirt build-up where the wiper sits if left at the same setting for a long time. I always tell folks to set all the pots at "0" if the amp isn't going to be used for a long time, as that prevents bad spots from happening right at your normal set-point for the controls .  |
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