I have three guitars: two Stratocasters and one Ibanez S. Their pickup configurations are SSS, HSH, and HH respectively. For the first Stratocaster, I decided to pick up some Dimarzio Injector pickups (noiseless stacked single coils) and had a local shop install them.

Something I notice is that I get hum still. Previously I only got hum in positions 1, 3, and 5, but this time I have hum in all positions. I don't have hum in the Ibanez in any position, but I do have hum in the second Strat in position 3. I'm assuming this isn't an amp or pedal issue and is strictly in the first guitar.

I notice that the hum is exacerbated with gain pedals (I have a fuzz and OD, the hum is more pronounced with both, especially turned up higher) but it's still evident when clean. Touching a metal part of the guitar (eg. tuning pegs, floating bridge) or even a metal part of my pedal board (eg. a switch), it goes away.

I'm not experienced with doing electrical work in guitars nor do I know much about how the wiring is done. I was told they were installed in parallel for positions 2 and 4. I do get hum in all positions, though.

Could they have been installed incorrectly, or is this expected for higher gain pickups? I want to reiterate it does not happen with my Ibanez which has hotter pickups to begin with.

  • 2
    Would the hum be close to a low G note (assuming your mains is 50Hz) ? In which case it's probably a mains hum. Does it happen wherever the amp is plugged in? Humbuckers are designed to reduce hum - hence the name. Bad/no earth on the guitars is possible. Back to the repairer is my suggestion.
    – Tim
    Oct 21, 2018 at 7:18
  • If the hum goes away by touching the pedals, this may give you a way to fix it, by grounding the pedals (either to the mains ground or via the amp). Oct 21, 2018 at 13:43
  • @YourUncleBob it goes away when touching anything metal in my setup. The input jack on my amp, a metal switch or knob on the amp or pedalboard, the tuning pegs or bridge, etc but only for this Stratocaster. It does not happen on my Ibanez (HH config) so I'm lead to believe the issue is with the Stratocaster.
    – gator
    Oct 21, 2018 at 15:50
  • It's not surprising that Fuzz and OD amplify the hum - amplifying whatever comes out of the guitar is part of their job description. And since the new pickups are constructed to be hum-resistant, it sounds like a grounding issue - some ground cable not connected properly. You say you had it done at a shop - why don't you take it back to that shop and have them have another look? Oct 22, 2018 at 6:27
  • @RichardMetzler I ended up bringing it to the same shop and they tried it on a couple of amps and were unable to reproduce the issue. They suggested a cable/pedal issue, so I tried plugged solely into the amp (and nothing else plugged into the same outlet) and still noisy. What strikes me as odd is it doesn't really happy with the other guitar with humbuckers, so why should it here? Maybe I should look into having it shielded.
    – gator
    Oct 22, 2018 at 22:59

1 Answer 1


Did they actually check it again in the shop? If you say it goes when touching something this seems like very much a grounding issue. If you didn't hear it in the shop, was it noisy? In bigger shops there are other people chatting, playing, .. and you might miss on a a hum you hear in a dead silent environment. They should open it, and check if the wiring is correct if it is the only one in your setup that's not working, it can only be the guitar..

One thing you could try, is open up the back of the guitar, and see if there are any BLACK cords, that are loose. There should be one going to your output jack, and one should go somewhere metallic on your guitar. You can see where the ground is, in this photo of a pickguard: https://www.bluestarmusic.com/DiMarzio-Paul-Gilbert-InjectorArea-67-Prewired-Strat-Replacement-Pickguard-White_p_2448.html

The one on the potentiometer (the lower part of the tone/volume knob), and the one on the output jack are the ones where it matters, you can see the output jack goes to the green box, from there the black goes on top of the potentiometer, to the other ones and also to the 5-way-switch. If one of them is a bit wonky, or even hangs loose then the soldering wasn't done correctly. You could even fix this with tape, but again, if you paid for it, I would demand they look at the wiring again.

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