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*Groan* What have I done wrong this time? (Guitar wiring- very low output on neck pickup)

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Dave_McDave_Mc Frets: 2461
in Making & Modding
Hi everyone,

I wired up my HSS Lag Strat with my new Oil City pickups and all the resistance readings seem to be roughly correct, but I'm not getting much output out of the neck pickup. The bridge and middle pickups seem to sound fine (they sound great, actually), but the neck pickup on its own is very quiet- pretty much silent at lower volume/gain settings, and a bit of output (but still far too quiet) if I use really high gain. Once I add the neck pickup to any of the other pickups, it doesn't sound right- pretty much what I would expect for the neck pickup being far too quiet combined with the much louder other pickup(s). I also think I'm getting a little more noise than I should on the neck pickup alone- and it sort of sounds like "something's not quite right" noise, if that makes sense.

Here's an artist's impression of how I wired it- the volume push-push adds the bridge pickup, and the tone push-push does a partial split on the bridge humbucker. (It's too late tonight to take the scratchplate off again, I'll take it off tomorrow to get a picture if no-one can figure out what the problem might be.)




I tried this same wiring scheme on another guitar a few months ago and it worked... of course that guitar was rear-routed so any wiring troubleshooting would have been much easier, lol. It had to go wrong on the scratchplate one, lol.

Does anyone have any idea what might be wrong? The single coils were a bit of a tight fit, so maybe something is shorting out somewhere (though it's a bit strange I'm getting the "right" DC resistance readings), or maybe I've done something silly with those resistors or the fancy wiring. I did change the selector switch (and also the pots) so maybe something is shorting out there. It's also possible, being a scratchplate-loaded guitar, that when I put it back together something which shouldn't is touching something else...

Here are the resistance readings:
Bridge: 9.48k
Bridge (partial split): 6.68k
Bridge + Middle (parallel): 3.79k
Bridge (partial split) + Middle (parallel): 3.25k
Middle: 6.25k
Middle + Neck (parallel): 3.17k
Neck: 6.26k
Bridge, Middle + Neck (parallel): 2.39k
Bridge (partial split), Middle and Neck (parallel): 2.16k
Bridge + Neck (parallel): 3.8k
Bridge (partial split) + Neck (parallel): 3.25k

I can't remember the exact readings from before I put them into the guitar, but IIRC the bridge humbucker measured out at roughly 9.6k (the coil being used in the split being ~5.3k), and both the neck and middle pickups had almost identical readings in the 6.3-6.4k region, with IIRC the neck pickup being actually very slightly higher in resistance.

Thanks in advance for any help you can give me, 

Dave :)
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Comments

  • FunkfingersFunkfingers Frets: 15262
    Check all solder joints. Likeliest explanation is weak ground connection for the neck pickup.

    Second most likely explanation is a defective selector switch. Those eight-contacts-in-line PCB switches are notoriously prone to failure under enthusiastic handling.
    You say, atom bomb. I say, tin of corned beef.
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  • ICBMICBM Frets: 74472
    If the neck pickup is reading the right resistance, check that it's magnetised.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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  • Dave_McDave_Mc Frets: 2461
    Funkfingers said:
    (a) Check all solder joints. Likeliest explanation is weak ground connection for the neck pickup.

    (b) Second most likely explanation is a defective selector switch. Those eight-contacts-in-line PCB switches are notoriously prone to failure under enthusiastic handling.
    Thanks :)

    (a) Will do, good call

    (b) Yeah I was wondering about that- it's a new one which I've never used before, it could well be faulty as you said. Is there any way to check if it's faulty?

    ICBM said:
    If the neck pickup is reading the right resistance, check that it's magnetised.
    Thanks John :) How do I do that? Or am I being an idiot and do I just need to touch it with something metal/magnetic (ferromagnetic? I should probably know these terms lol) to see if it sticks? :D 
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  • ICBMICBM Frets: 74472
    Dave_Mc said:

    Thanks John :) How do I do that? Or am I being an idiot and do I just need to touch it with something metal/magnetic (ferromagnetic? I should probably know these terms lol) to see if it sticks? :D 
    Yes, just that. A small screwdriver or an Allen key should stick to the poles.

    I once had a couple of Duncan pickups like this at separate times - one wasn't magnetised at all and the other, quite bafflingly, had the top E and B poles unmagnetised but the rest were OK. How, since I think they put the whole thing in a magnetiser after construction, I do not know! But that was absolutely the fault.

    Getting a correct resistance reading means the coil is OK. No output then means it's either not connected electrically (faulty cable or switch) or not magnetised. But if it sounds oddly like the pickup is sort-of working when combined with the middle, the switch and the cable must be OK, which only leaves a magnetic problem really.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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  • Dave_McDave_Mc Frets: 2461
    It's not magnetised! :D You're a total ninja, John. :) Thanks (again!) :D 

    Funnily enough, I thought I checked that myself last night before I posted the thread- but I was plugged in and sort of testing whether I heard a "click" through the amp when I did it (which I sort of did).

    I guess that means I have to send back the pickup to be magnetised?
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  • FunkfingersFunkfingers Frets: 15262
    ICBM said: 
    I once had a couple of Duncan pickups like this at separate times - one wasn't magnetised at all.
    I had the same issue with a Duncan Custom Shop pickup. (The precursor to the production line Twangbanger model.)

    •

    It is possible for pickup magnets to be degaussed by strong electric fields. Andy Summers describes this happening to the bridge pickup in his famous mongrel Custom Telecaster during a rail journey.
    You say, atom bomb. I say, tin of corned beef.
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  • Dave_McDave_Mc Frets: 2461
    I remember my old supervisor used to complain that the NMR machine kept killing his debit cards :D His office was just above it.

    I don't think I have any strong magnetic fields here, though. None of my other pickups have had that happen. Anything could have happened in the post, though, I would imagine.
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  • ICBMICBM Frets: 74472
    edited December 2021
    Dave_Mc said:
    It's not magnetised! D You're a total ninja, John. Thanks (again!) D
    Theory. Logic. Experience.

    Dave_Mc said:

    Funnily enough, I thought I checked that myself last night before I posted the thread- but I was plugged in and sort of testing whether I heard a "click" through the amp when I did it (which I sort of did).
    You will get a small click with something ferromagnetic, especially if it's slightly magnetised itself - many screwdrivers are - even if the polepieces aren't, since it still produces a (small) disturbance in the coil.

    Dave_Mc said:

    I guess that means I have to send back the pickup to be magnetised?
    Yes. Either it's somehow been demagnetised in the post - a bit unlikely if the others arrived at the same time and are fine - or Ash's magnetiser is on the blink... or it just somehow got missed!

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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  • FunkfingersFunkfingers Frets: 15262
    Dave_Mc said:
    I guess that means I have to send back the pickup to be magnetised?
    You can do it yourself with a pair of neodymium magnets BUT you need to be very cautious. 

    The attraction between two neodymium magnets can be so strong that they snap together with enough force to break bones.  :o
    You say, atom bomb. I say, tin of corned beef.
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  • Dave_McDave_Mc Frets: 2461
    ICBM said:
    Dave_Mc said:
    It's not magnetised! D You're a total ninja, John. Thanks (again!) D
    (a) Theory. Logic. Experience.

    Dave_Mc said:

    Funnily enough, I thought I checked that myself last night before I posted the thread- but I was plugged in and sort of testing whether I heard a "click" through the amp when I did it (which I sort of did).
    (b) You will get a small click with something ferromagnetic, especially if it's slightly magnetised itself - many screwdrivers are - even if the polepieces aren't, since it still produces a (small) disturbance in the coil.

    Dave_Mc said:

    I guess that means I have to send back the pickup to be magnetised?
    (c) Yes. Either it's somehow been demagnetised in the post - a bit unlikely if the others arrived at the same time and are fine - or Ash's magnetiser is on the blink... or it just somehow got missed!
    (a) Yeah :D I guess this is another thing I'll remember to check for in the future before I wire pickups into the guitar!

    (b) Now you mention it I think I did it with a screwdriver yesterday- I was adjusting the pickup heights so it was the easiest thing to hand (and I think it is slightly magnetised, as you say). Today I did it with an allen key, to be sure.

    (c) Thanks, I'll send it back :) 
    Funkfingers said:
    Dave_Mc said:
    I guess that means I have to send back the pickup to be magnetised?
    You can do it yourself with a pair of neodymium magnets BUT you need to be very cautious. 

    The attraction between two neodymium magnets can be so strong that they snap together with enough force to break bones.  :o
    Wow, I think I'll send it back in that case! :D 
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  • normula1normula1 Frets: 662
    If you have access to some kid's geomags, they're just a pair of tiny neo magnets with a stèel bar in between them. Put it on top of the pole piece and pull away vertically. Rinse and repeat several times. I've used this technique to reverse the magnetic polarity on a Strat pickup in situ that I was having phase issues with. 
    It's also useful to tame the G on a staggered Strat pickup on flat radiused guitar.1 
    my trading feedback: http://thefretboard.co.uk/discussion/115582/normula1
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  • Dave_McDave_Mc Frets: 2461
    ^ Thanks, but I don't think I have any of those :D I'll just send them back- don't want to ruin the pickup doing something silly.
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  • Dave_McDave_Mc Frets: 2461
    edited December 2021
    Just updating this- I got the pickup back from Ash (was super-quick- I got it the day after he received it and I'm in Northern Ireland!) and it's working now and sounds great  EDIT: I should probably add- he also refunded my postage and paid extra to get it back to me so quickly (which I didn't ask for)- great service all round! :) 
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