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Post by nomadguitar on Feb 9, 2022 11:08:51 GMT -7
Hi everyone, first post here.
I recently got a Carmen Ghia that has quickly become my main amp for gigs, rehearsal, etc.
I've been experiencing a weird problem with the volume pot. At first, I always had a little volume even though it was turned down all the way, I didn't think much of it.
But the last two rehearshals stranger things have occurred.
The volume pot then did completely turn down the volume last week, but this week, I turned the amp on, with the same setting we played last week, and it was extremely loud, like it was turned up from 2-3 to 5-6. It was so loud the amp was distorting (oh it sounded good though!)
I had to turn the volume all the way down, but it was still loud, and I rehearsed all night with the volume all the way down.
I am getting no crackling or noise otherwise.
Is the pot bad? Another cause?
Thanks
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Post by purpletele on Feb 9, 2022 11:52:54 GMT -7
Hi everyone, first post here. I recently got a Carmen Ghia that has quickly become my main amp for gigs, rehearsal, etc. I've been experiencing a weird problem with the volume pot. At first, I always had a little volume even though it was turned down all the way, I didn't think much of it. But the last two rehearshals stranger things have occurred. The volume pot then did completely turn down the volume last week, but this week, I turned the amp on, with the same setting we played last week, and it was extremely loud, like it was turned up from 2-3 to 5-6. It was so loud the amp was distorting (oh it sounded good though!) I had to turn the volume all the way down, but it was still loud, and I rehearsed all night with the volume all the way down. I am getting no crackling or noise otherwise. Is the pot bad? Another cause? Thanks I would check to see that the pot is securely tightened to the chassis, that connection is a ground connection. If that Pot is tight then I would do the chopstick test on the pot and wires while the amp is on, provided that you are comfortable with an exposed chassis, etc. If you can affect a change with the chopsticks then you might have found your problem, like a solder joint that needs to be re-flowed. If that doesn't work, I would change the power tubes. If that doesn't work, then I would roll the Pre-amp tubes one by one. It sounds like a bad connection on the pot. Others may have another idea. Let us know what you find.
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Post by GuitarZ on Feb 9, 2022 13:00:27 GMT -7
Good advice above. My first suspect would also be the ground connection.
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Post by Chilly Gibbons (Todd T.) on Feb 9, 2022 13:35:13 GMT -7
And possibly some contact cleaner like DeOxit to tidy things up a bit.
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Post by nomadguitar on Feb 9, 2022 15:08:58 GMT -7
Thanks for the info, I'll try that first and follow up.
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Post by nomadguitar on Feb 10, 2022 17:58:51 GMT -7
So I did the chopstick test, and the group of resistors/caps attached to the tone pot seems to be causing the volume problem. When I move the resistors/caps (gently) I get volume fluctuations. What is that red stuff on it? So I should resolder those points? ibb.co/b2nM00B
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Post by DRZ on Feb 10, 2022 19:08:07 GMT -7
That is an old Ghia pre ETL. Looks like the Green wire the connects between the Tone pot and the Volume pot is touching the chassis and shorting the volume signal. If that's not it that amp will need to send in so we can find the issue. It will need to be benched as there is no online fix .
DR.Z
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Post by nomadguitar on Feb 10, 2022 23:39:17 GMT -7
Thanks so much for the response.
It think I got it, touched up the solder, and move the wire away from the chassis. So far, so good.
I really love this amp, and has become my #1 very quickly, over my two handwired Voxes.
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