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Topic: Help! Vegas 400 amp making high pitch noise |
Alan Judson
From:
Hamilton, Ontario, Canada
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Posted 25 Oct 2022 4:58 am |
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When I turn on my Vegas 400, it makes a high pitch whistling/feedback sound.
It gets worse as you turn the gain up.
This happens when nothing is plugged in and when something is plugged in.
The second channel works better, but you hear the feedback very faintly.
Where should I start troubleshooting this? I don't know much about electronics. |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 26 Oct 2022 5:59 am
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| check the pots- esp the mid and the shift |
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Alan Judson
From:
Hamilton, Ontario, Canada
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Posted 26 Oct 2022 6:38 am
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Thanks Jim.
I know there are no dumb questions, but...
What would I be checking for? 
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 26 Oct 2022 6:44 am
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| It's not uncommon for those 2 pots to go out and frequently the symptom is a very loud pop or high pitched squeal. About 1/2 the time it can be minimized or fixed by rotating the pot back and forth a bunch of times (100+/-) and worse come to worse replacing the pot. Most of the time it is because once set most of us don't change it. |
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Alan Judson
From:
Hamilton, Ontario, Canada
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Posted 26 Oct 2022 7:38 am
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Thanks - I'll create a game for my kids to rotate the pots - lol.
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PEDAL STEEL TEES: https://etsy.me/3gHuPe1
Always FREE Shipping.
15%OFF for SGF folks with code: STEELGUITARFORUM |
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Richard Sinkler
From:
aka: Rusty Strings -- Missoula, Montana
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Posted 26 Oct 2022 11:22 am
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| Jim Palenscar wrote: |
| It's not uncommon for those 2 pots to go out and frequently the symptom is a very loud pop or high pitched squeal. About 1/2 the time it can be minimized or fixed by rotating the pot back and forth a bunch of times (100+/-) and worse come to worse replacing the pot. Most of the time it is because once set most of us don't change it. |
And make sure the power is off when you do it. I shortened my life expectancy by five years after the loud pop when rotating the mid controls. Had to buy new undies too.
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Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting. |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 26 Oct 2022 7:24 pm
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| I agree Richard- like a gunshot! But I just turn it way down and live w it hoping it goes away. |
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George Biner
From:
Los Angeles, CA
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Posted 31 Oct 2022 7:57 pm
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High pitched squealing means the amp is oscillating -- something has broken or come loose -- loud popping also means that something in the signal path is loose, like a solder joint -- the amp needs to be taken apart and fixed.
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Guacamole Mafia - acoustic harmony duo
Electrical engineer / amp tech in West Los Angeles -- I fix Peaveys
"Now there is a snappy sounding instrument. That f****r really sings." - Jerry Garcia |
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Dale Foreman
From:
Crowley Louisiana, USA
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Posted 1 Nov 2022 12:01 pm Noise
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Unplug the reverb tank and see if it stops.
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Rittenberry Prestige(2) |
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