Buzzing that comes and goes in my 5fa2?

Discussion in 'Shock Brother's DIY Amps' started by PurpleStrat, Apr 2, 2020.

  1. PurpleStrat

    PurpleStrat Tele-Meister

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    I'm getting this buzzing that lowers the volume if I'm playing that comes and goes. I've even got it to go away by tapping on components but I can't tell where it's coming from. Any ideas?
     
  2. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    "I've even got it to go away by tapping on components"

    That's a clue. Tap more methodically with a chopstick and see if you can isolate it down to a single wire or component. Could be a bad connection that causes issues after it gets hot.
     
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  3. PurpleStrat

    PurpleStrat Tele-Meister

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    That's what I did but it would be near the big caps one second then on the input the next. Basically I could to it anywhere and it would come to. Makes me think it's a ground issues but IDK. I even changed a few parts like the first two big caps, the couponing caps and took out the tone control. Stiil happens.
     
  4. Uncle Daddy

    Uncle Daddy Tele-Afflicted

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    Check the jack socket nuts are tight, input and output.
     
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  5. Lowerleftcoast

    Lowerleftcoast Tele-Holic

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    Tube?
     
  6. King Fan

    King Fan Poster Extraordinaire

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    If tapping *anywhere* makes it happen, a tube is possible. Swap out the preamp tube first -- if no better, then try the power tube. Loose tube springs are a common crackle cause, but may be more common on old sockets. But dirty / crooked pins can even do it by making poor contact with the springs.

    More generally, any loose connection could do it, or a starved or cold solder joint. Poke each solder joint with your chopstick and try wiggling each wire.

    Wiggle your input and speaker plugs -- and make sure the shunt is well-separated visually when a jack is inserted. Partial / variable ground on a shorting jack is common.
     
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  7. PurpleStrat

    PurpleStrat Tele-Meister

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    Ive tested the preamp w d power tube but I just had to order a new rectifier tube. It's a Chinese tune a 6z4. I'm upgrading it to a Russian 6C4P-EV while I'm at. Might be the issue but if not it's good to ha e a replacement.

    Also the volume pot looks suspect so I ordered some good pots. Not gonna be much left in the amp that was Chinese.
     
  8. Nickfl

    Nickfl Tele-Afflicted

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    Cold solder joint. Somewhere you've got a wire stuck into a blob of solder that is physically captured by the solder but loose within it. When you find it, you'll see that if you twist it the wire is not actually melted to the solder but turns freely in the joint, this problem manifests as static and intermittent sound.
     
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