Reverb hum

Discussion in 'Amp Input - Normal or Bright' started by Stratattack72, Sep 15, 2021.

  1. Stratattack72

    Stratattack72 Strat-O-Master

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    Got me a Peavey Blazer that I got from an estate sale. The amp sounds great . I had to resolder the input jack , but other then that it's been pretty good . The bad is the reverb hums like crazy . I replaced the original with a Accurtronics aftermarket one it's the blue one . It has a plastic body and whenever it is placed within the confines of the amp it starts to hum . And if you really crank the reverb it sounds like it is going to blow . Now if I put it outside of the amp it behaves normally . I have tried cleaning the jacks ect , but running out of ideas here . Any help is much appreciated. Thanks.
     
  2. Triple Jim

    Triple Jim Guy Who Likes to Play Guitar Silver Member

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    Did you follow the wiring instructions and ground the correct terminal(s)?

    You could try shielding the tank and grounding the shield.
     
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  3. Stratattack72

    Stratattack72 Strat-O-Master

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    There was no instructions with it . I am fairly experienced with wiring . This was happening with the old tank as well. exactly the same thing. I did think about shielding the tank so may try that .
     
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  4. Triple Jim

    Triple Jim Guy Who Likes to Play Guitar Silver Member

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    I'd guess that their website has wiring information. If I'm wrong you should be able to email or phone them and ask.
     
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  5. Impulsive guppy

    Impulsive guppy Strat-O-Master Silver Member

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    A lot of amps with built in reverb hum in the way you describe , unfortunately.
     
  6. Stevem

    Stevem Senior Stratmaster

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    The outout side of any reverb pan is like a guitar pickup, and as such if it's close to the amps power transformer it will pick up 60 HZ hum .

    This means the output side of the pan needs to be mounted as from away from the power transformer as possible, even if you need to add extension cables to for instance mount it to the floor of the amp cabinet.

    Also cable wise the input side of the pan should not read as being grounded to the amps chassis, only the output side of the pan is grounded to the chassis as can be seen when you look at the schematic of the amp.

    If with the pan disconnected from the amp if you read zero ohms ( a short ) between the shell of the pans input jack and output jack then you have the wrong reverb pan .
     
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  7. mutato

    mutato Senior Stratmaster

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    To me it sounds like dirty RCA cables that connect the tank to the amp. I sometimes have some issues with my 1977 PR and pedal cable that activate the reverb/tremolo circuit. It sometimes get a little noisy. I have to wiggle the jacks a little bit to dislodge corrosion and it works well after that.
     
  8. hecubus

    hecubus Strat-Talker

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    On one of my amps, the reverb pan is too close to the speaker. The interaction between the speaker magnet and the pan causes the hum. I put an old folded up t-shirt between them and the problem was solved. I am guessing a piece of foam might yield the same results.
     
  9. mutato

    mutato Senior Stratmaster

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    Speaking of wrapping pan, that is DEF a good thing to do. I had an old 60's SANO amp. The pan was side mounted and hard-screwed to cabinet and when you turned it up it started to ring louder and louder. Basically a feedback. I ended up buying a vinyl tank bag and loosely mounted it. Also, a good trick is to cut a piece of cardboard the tank dimensions and lay underneath the tank within the vinyl bag. Feedback issues were gone.
     
  10. Wound_Up

    Wound_Up CUSTOM USER TITLE Silver Member

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    Is it isolated from the cab with rubber/silicone feet or bolted straight to it solidly?

    They used those blue plastic tanks in the Stage Right 15w combos from Monoprice when they first came out and no one liked it. Most people ended up swapping it out for a standard short tank after they replaced the connectors with rca jacks.
     
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  11. Stratattack72

    Stratattack72 Strat-O-Master

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    It bolts right to the cab . No RCA Jacks with this one .