Mesa fifty/fifty strange sound, please help

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j4q0
RM100
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Joined: Tue Feb 26, 2013 1:37 am
Location: Toronto

Mesa fifty/fifty strange sound, please help

Post by j4q0 » Sat Mar 07, 2015 10:26 am

I'm not sure if this would be the appropriate place for this so here it goes.

I have a Mesa Fifty/Fifty that has been stored inside a rack case for months, yesterday I powered it up to double check everything is OK before selling it and found myself with this strange sound:

http://youtu.be/EDt3AdcmnIY

Both sides of the amp work perfectly and the amp sounds as it should, the sound is not in the audio signal, it comes from a vibration of the main transformer which you can feel as you lay your hand on the chassis.
I've never had a problem with this amp before storing it so this just came out of the blue so to speak.
Does anyone have an idea of what the problem would be?
I hope I don't need to replace the transformer.

suphuckers
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Post by suphuckers » Sat Mar 07, 2015 10:29 am

It's the plates of the transformer j4q0. They can get loose over time. They vibrate against each other.
"Dude, you're easily the gnarliest guy I've seen around here in years"

59' Sears Wish Book Cowboy Guitar w/ Christmas Box, AXL Acoustic Guitar Pickup w/ E-pin Jack, Marshall MS-2 1/2 Stack Classic. ohhh, and some modules.

j4q0
RM100
Posts: 180
Joined: Tue Feb 26, 2013 1:37 am
Location: Toronto

Post by j4q0 » Sat Mar 07, 2015 10:34 am

Could you give me any directions as to how can I fix this, or would I need a new transformer?
suphuckers wrote:It's the plates of the transformer j4q0. They can get loose over time. They vibrate against each other.

suphuckers
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Posts: 689
Joined: Tue Aug 05, 2014 8:32 pm
Location: Under a Tree Near the Stage Coach Inn Museum

Post by suphuckers » Sat Mar 07, 2015 1:28 pm

j4q0 wrote:Could you give me any directions as to how can I fix this, or would I need a new transformer?
suphuckers wrote:It's the plates of the transformer j4q0. They can get loose over time. They vibrate against each other.
Open it up and see if it's loose where it's mounted. If the plates themselves are vibrating there isn't much that you can do (that I know of). You can try disconnecting the ground and using different power sources. Sometimes that stuff can make a transformer hum. ..but like I said if its the plates... I think you just have to replace it.

Take it to a friends house or work and see if it hums there. (not kidding)

Before I'd even think about replacing the transformer, I'd eliminate ALL chances that it has anything to do with the power source you have it plugged into.
"Dude, you're easily the gnarliest guy I've seen around here in years"

59' Sears Wish Book Cowboy Guitar w/ Christmas Box, AXL Acoustic Guitar Pickup w/ E-pin Jack, Marshall MS-2 1/2 Stack Classic. ohhh, and some modules.

j4q0
RM100
Posts: 180
Joined: Tue Feb 26, 2013 1:37 am
Location: Toronto

Post by j4q0 » Sat Mar 07, 2015 3:33 pm

So,
I also noticed a similar hum coming out from my studio monitors so I thought about what gear connected to the same power source had changed in the last couple of weeks, the only thing was 2 humidifiers.
So I turned them off and no more hum. The hum will come back only if both units are on the low setting.

Thanks for the suggestion suphuckers, I thought about the power source being contaminated by something but was puzzled because the rest of the gear didn't have that problem.

Problem solved!

suphuckers
Lynch Box
Posts: 689
Joined: Tue Aug 05, 2014 8:32 pm
Location: Under a Tree Near the Stage Coach Inn Museum

Post by suphuckers » Sat Mar 07, 2015 5:46 pm

Awesome! When you said it wasn't coming out of the speakers that was a bad sign as far as a ground loop. I had some ground loops that drove me crazy a week ago. I'm glad for you that's all it was.
"Dude, you're easily the gnarliest guy I've seen around here in years"

59' Sears Wish Book Cowboy Guitar w/ Christmas Box, AXL Acoustic Guitar Pickup w/ E-pin Jack, Marshall MS-2 1/2 Stack Classic. ohhh, and some modules.

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