A Humming Buzz

Discussion in 'Epiphone Guitars' started by Dean James, Jan 5, 2016.

  1. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    I recently upgraded an Sheraton II with a new wiring harness, including pots, switch & plug, & a new pair of pickups. It sounds good, but shortly after the new components were installed, a buzzing hum started making itself heard.

    Grounding problem, I said, & returned to the techs who did the installation. They couldn’t hear the buzz. Life being much like a situation comedy, when I got the guitar home, the buzz was still there. I’ve had good service from this shop, so am inclined to give them the benefit of the doubt.

    On its return the buzz had changed both its sound & the conditions under which it appeared. Previously it was the same at all settings, & stopped when skin touched metal. Now that no longer stopped it, & it sounded different under different settings. Some were clear, some no longer worked at all. There was also a new sound, a gurgling tick-tock which sounded pretty digital to me.

    I now wonder if the problem might be with the amplifier. Before I rent an amp & guitar & try out diagnostic mixing & matching, I’d like to be better informed. Here are my questions:

    This is a five year old hybrid amp, part digital, part tube. How long does a typical tube last before needing replacement?

    The amp never had this problem before. Could it be that, before its upgrades, the guitar was never delivering enough signal to make an existing problem audible? I also tried an acoustic-electric guitar without hearing the buzz. Again, could that be due to insufficient signal from the guitar?

    Last, the guitar’s new pickups are not wax-potted. Reviews say this can, in some circumstances, cause them to become “microphonic.” I haven’t a clue what that might sound like, but is it worth considering?

    Thanks for your help!
     
  2. BGood

    BGood Well-Known Member

    Messages:
    4,245
    Likes Received:
    4,946
    Joined:
    Jan 25, 2015
    If the tech says it doesn't buzz at the shop through his amp, it sounds like the problem is at your end, your amp. What is the amp ?

    A microphonic pickup will feed back at high volume or/and overdrive and when you speak close to it, you might hear your voice through the amp like with a cheap microphone.
     
  3. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016

    Yes, my amp's what I'm considering now. It's a Fender Super Champ XD, ca 2010-11. The guitar's an Epiphone Sheraton II with Duncan Seth Lover pickups. Thanks for the description of microphonic pickups.
     
  4. ScottMarlowe

    ScottMarlowe Well-Known Member

    Messages:
    905
    Likes Received:
    767
    Joined:
    Jan 27, 2015
    OK here's the $64,000 question. Is it 60Hz or 120Hz (or 50/100 if you're in europe)?

    60Hz hum
    120Hz hum

    60Hz hum comes from external RF sources like dimmer switches or lighting or appliances. 120Hz hum comes from your rectifier section in the amp.

    Here's a good video from Uncle Doug about hum
     
  5. Alty

    Alty Well-Known Member

    Messages:
    848
    Likes Received:
    776
    Joined:
    Jan 24, 2015
  6. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    Closer to 120, I'd say. I'll add that video to my research list. Please send the $64,000 in non-consecutive fives, tens, & twenties, thanks.
     
    IGRocker likes this.
  7. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
  8. ScottMarlowe

    ScottMarlowe Well-Known Member

    Messages:
    905
    Likes Received:
    767
    Joined:
    Jan 27, 2015
    Here ya go:

    [​IMG]
     
    IGRocker and Alty like this.
  9. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    This is becoming squirrelly. It now seems the pickups have been connected incorrectly.

    I turned the guitar over to the techs for them to install a new wiring harness & new pickups. When it returned, it had the buzzing hum we’ve been diagnosing.

    Also, the control knobs layout had been flopped. That is, the volume and tone knobs nearest the center of the guitar, which formerly controlled the neck pickup, now controlled the bridge, and vice versa. I confirmed this by setting the controls to ten and to zero in turn, then tapping the pickup poles. The three-way switch, which formerly operated vertically, had rotated and now operated horizontally.

    (Although I wondered how this happened, I didn’t really mind it. To me, this layout makes more sense, visually & operationally. It seems to interrupt my mental/musical flow less when used.)

    In reading up on the subject, I found a story of some poor soul whose pickups had been installed backwards: neck pickup in the bridge cavity and vice versa. Maybe that explained the control layout change — it wasn’t the pots that were flopped, it was the pickups.

    Before handing everything over to the techs, I had Sharpie-markered initials on each pot indicating its assignment: NV, NT, BV, BT. Just trying to be helpful. Not hard to figure out: place the harness with the amp plug at the correct end, arrange the pots into a nice easy parallelogram, match the existing controls.

    Inside the f-hole, on the pot installed where the bridge volume control had been (the one I currently thought was mistakenly occupied by the neck volume pot) were the initials BV. On what should have been the neck tone pot was indeed written NT. I couldn’t see the other two, but it’s reasonable to infer they are also correctly placed.

    But they’re controlling the incorrect pickups. So are the pickups mis-installed? I loosened the strings, undid the frame, gently lifted out the neck pickup to find on its back a sticker saying Neck.

    So, the only conclusion left is that the pickups and the pots are in the right places but are connected wrong, causing the controls to affect the wrong pickups.

    Have I figured this out correctly?

    This is a 335-style instrument with no back hatch, so any work of this sort must be done through the lower f-hole. Now you know why they call them that. These are pickups with four-conductor cables connecting to a twenty-one sound J Page-style wiring harness, so the installer is attempting to deal with correctly connecting sixteen small wires in the cramped darkness inside an f-hole. It’s a famously awkward and tedious task.

    Finally, the pickups are extremely loose in their frames. They can wobble back & forth, neck to bridge, as much as 1/8”. They are also at extremely different heights. The neck is very low, bridge very high, with a large difference between them. Do you suppose this could have been necessitated by trying, after wiring them, to get the appropriate sounds out of incorrectly-connected pickups?

    As always, thanks for your thoughts.
     
  10. ScottMarlowe

    ScottMarlowe Well-Known Member

    Messages:
    905
    Likes Received:
    767
    Joined:
    Jan 27, 2015
    I'd guess it's either wired wrong, or that there are cold solder joints.
     
    RTH likes this.
  11. BGood

    BGood Well-Known Member

    Messages:
    4,245
    Likes Received:
    4,946
    Joined:
    Jan 25, 2015
    My guess would be a toggle problem, wired backwards and/or maybe a short on it.
     
  12. MaineTim

    MaineTim Active Member

    Messages:
    241
    Likes Received:
    240
    Joined:
    Sep 27, 2015
    Change of plan...
     
    Last edited: Jan 8, 2016
  13. eS.G.

    eS.G. Well-Known Member

    Messages:
    2,288
    Likes Received:
    1,786
    Joined:
    Jan 29, 2015
    Is this a humming buzz or the more annoying buzzing hummmmm????
     
  14. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    Squirrelly. New options keep presenting themselves...
     
  15. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    ...leading to changes of plan.
     
  16. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    Both, but only when I listen in reverse.
     
    eS.G. and IGRocker like this.
  17. IGRocker

    IGRocker Well-Known Member

    Messages:
    2,333
    Likes Received:
    1,437
    Joined:
    Jan 20, 2015
    I think this new guy is growing on me... Welcome to the forum! :rofl:
     
  18. eS.G.

    eS.G. Well-Known Member

    Messages:
    2,288
    Likes Received:
    1,786
    Joined:
    Jan 29, 2015
    Dont play it backwards........DON'T PLAY IT BACKWARDS!!!!!

    ---you'll ruin your records and your needle and have to buy more!!!!!----
     
  19. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    Thanks for the welcome, but be careful. Warts grow on people, too.

    If I may tangent slightly, Well Done to David Bowie. He helped rescue rock from blues changes.
     
    eS.G. and IGRocker like this.
  20. Dean James

    Dean James New Member

    Messages:
    10
    Likes Received:
    6
    Joined:
    Jan 4, 2016
    Not to worry, I meant hearing backwards.
     
    eS.G. likes this.

Share This Page