A buzz or a hum.

Discussion in 'Epiphone Guitars' started by King B, Jul 10, 2018.

  1. King B

    King B Member

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    Ok, so I really have some Epiphone guitars but I can't show you them just yet because I don't know how. So imagine this Purpleheart LPII that I just finished. The one with the figured Purpleheart head stock and jet black fretboard? That's right, that's the one. Any who, I've replaced the cheap factory pups with some less cheap factory pups (from a Standard) and now my amp has a buzz or hum that goes away when I touch the strings. I have a 2nd LPII and...no buzz. So I have a few guesses as to what the problem might be but I could use some FEEDBACK. And then the pictures work.
     

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  2. BGood

    BGood Well-Known Member

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    Sounds like a ground problem. When you played in the wiring, you probably pulled or cut the ground wire going to the bridge post bushing.

    Check in the control cavity, there's a wire that goes in a hole that leads to the closest bridge post, if you pull on it gently and it comes out, there's your problem.

    If there is resistance, connect a clip wire to a ground in the cavity and clip the other end to a string to see if that cuts the buzz. If it does, you'll have to pull the bridge bushing out and reposition the wire in there so it makes contact.
     
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  3. Raiyn

    Raiyn Well-Known Member

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    Yup. Bad ground.
     
  4. Juke Box

    Juke Box Active Member

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    Also remove the output jack and check out the solder joints. Make sure there is good contact to the plug too. A lot of noise issues are due to issues in this area. Visually observe how well the cord contacts when you plug it in

    Do this with out power.
     
  5. vomer

    vomer Well-Known Member

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    What they said above is good. And, an anecdote which may or may not be helpful. A while ago I made a wiring harness for a Peavey Rockingham hollowbody. All in braided wiring, and with humbuckers. It should have been as quiet as anything could be, but I had a buzz. I couldn't figure it out and I wasn't going to put the harness in the guitar until I had it sorted. I built it in a cardboard box top with holes for the pots and jack socket, on my table. I knew the wiring and the soldering were good and all the pots were working. It was so frustrating I posted about it on another forum, with a pic. When I looked at the pic I realised what the problem was. (Why I couldn't 'see' it in real life I don't know.) The amp I was testing it with was underneath the table. It was solely the proximity to the amp which was causing the buzz. I put the harness in the guitar, put it on my lap to play it maybe 3 feet away from the amp and it was fine.

    Short version, some buzz which goes away when you touch the strings can be normal, if it's not severe. Have you compared your new pups with your other LP in exactly the same playing circumstances, i.e position and distance from the amp, same time of day, (domestic appliances on the circuit, same lights on) etc?
     
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  6. BGood

    BGood Well-Known Member

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    Always worst just after sunset, a well known fact.:cool:
     
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  7. King B

    King B Member

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  8. King B

    King B Member

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    Yeah. I think it's all a grounding issue. No one mentioned my poor soldering skills which I believe to be most of the problem. It looks like I had to pee. Also brings up equipment problems. What soldering iron is recommended? Thanks for everyone's input.
     
  9. Davis Sharp

    Davis Sharp Well-Known Member

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    When I started to mod guitars (about 2.5 years ago), i bought a soldering iron. I left big blotches of solder all over the pots and switches. Now, i leave small dots. Who knew it takes this long to break in a soldering iron? :rolleyes:;)

    I started with a set like this, but with fewer pieces and a non-variable iron. The stand is nice, but after a while the heat gets to the plastic insert and it breaks.

    https://smile.amazon.com/gp/product/B00KR1CXTS/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
     
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  10. Raiyn

    Raiyn Well-Known Member

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    I use a 40 watt Weller. It's served me well through guitar mods and today I used it to upgrade the speakers in our new (to us) car.

    As for solder, I greatly prefer 63/37 rosin flux core. It's eutectic, which basically means it's either a liquid or a solid, you don't get that "plastic" stage like in 60/40.
     
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  11. DPaulCustom

    DPaulCustom Well-Known Member

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  12. DPaulCustom

    DPaulCustom Well-Known Member

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    Just to save a headache, always solder with the pots at '0', & stay towards the center of the pot when grounding
     
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  13. King B

    King B Member

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    Oh man! So much good information. Thanks again for all the input. I'm using a Weller 70 watt. I'm using the solder that came with it. I have concerns about over heating the components and I don't know why zeroing out the pots sounds right but it does. I'm getting ready to strip another LPII and I have a complete and new 339 assembly to go in it. I was pretty good with the soldering gun in electronics class but that was 1980! I'll be practicing on some junk parts. So here is another question. Will I be able to use the 4 wire system in an LPII? I think I can but please enlighten me.
     
  14. DPaulCustom

    DPaulCustom Well-Known Member

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    When you put the pot at zero, even if you do burn or get it too hot, any short, or disturbance to the conductive tract will be in an are that's not used much.

    If the 339 kit has push/pull pots, you'll have to see if the LPII cavity is deep enough to allow for them (I think you should be fine).
     
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  15. BGood

    BGood Well-Known Member

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    You can use a 4 wire pup with any push-pull pot.
     

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