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Non ADA Gear => Guitars => Guitar Wiring => Topic started by: rabidgerry on November 22, 2018, 11:36:59 AM

Title: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 22, 2018, 11:36:59 AM
Hi guys, I need help with this wiring.  I have wired this mod in one of my guitars because it had the mod done to it when I first bought it and I've always thought it was neat and descrete.

However when I changed pickups many moons ago and wired up the new bridge pup things have never been quite right.

So the functionality was working yes, but to me the signal has always seemed quite strangled or something.

Also the push pull I thought had got damaged from something careless done by me.

So I swapped it out last night and wired up following this diagram (see attached) and it all works ok but again sounds strangled on full humbucker and also I get mega noise when I touch the dam control knob.  The noise to me sounds as though I am touching the signal end of a guitar cable.

I am not sure but I believe this has something to do with the neck pickup which only has a signal wire and earth and a shield.  However this pickup can be split, because when I first bought this guitar it had two pickups in there with only three wires and they were both wired to the push pull and both split with out any issues.  So something must have been different but I cannot for the life of me figure it out.  Can someone please help?

***************Important****************
I might need to point out that the three wire pickup works like this, the white wire is a join between positive and negative.  I have tested this and know it to be true.  If I connect multimeter to the shield and to this white wire and leave out the red wire entirely I get half the humbucker resistance (about 4k).  If I connect multimeter to the red wire and the shield wire I also get 4k.  If I connect multimeter to the white wire and the red wire and leave out the shield I get 8k.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on November 22, 2018, 02:41:12 PM
Are both PU's irongear pickups?

If the bridge PU only has signal,ground shield wires you can't split them.

Seems like the bridge PU is wired in parallel?

What about the green wire?
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 22, 2018, 03:07:31 PM
Oh no, silly me I meant to wipe that bit out.  The pickups are a dimarzio in the bridge and the original stock pickup that was in already.

So the dimarzio has the usual 4 conductors and a shield.

The switch right now functions as it should, it splits the neck and the bridge pickup when pulled but I get this shit noise when I touch the control.  Like when your finger touches a cable signal end.

Originally when I bought this guitar it had the two three wire pickups installed and also had the mod working without issue, but then I swapped the bridge out for a dimarzio.  Which then complicated things or made me screw up somewhere.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on November 23, 2018, 08:34:31 AM
Is the pot chassis tied to ground?
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: Kim on November 23, 2018, 08:19:46 PM
The diagram will be misleading if you're using a DiMarzio pickup instead of the IronGear because the color codes aren't the same.  The IronGear in the diagram has the Green/White together, Black Ground while the DiMarzio needs the Black/White together, Green Ground.

(https://i.imgur.com/0hLGUHT.jpg)
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: vansinn on November 24, 2018, 01:01:25 AM
The diagram is using ground symbols, which should never be there!
All ground wires should must be connected to a single [ground-summing] point, usually on the volume potmeter chassis.
Solder a grounding wire from the tone potmeter chassis to the volume potmeter chassis.
From the volume potmeter, run a shielded cable to the jack socket.

Apart from this, the electronics cavity should be shielded, which should be connected to the volume pot chassis.

Do note that running a grounding wire from the tone potmeter and the switch chassis to volume potmeter [common ground summing point], can create a ground-loop if the potmeters are mounted onto cavity shielding.
In this case, it may be better to rely on the grounding of tone and switch chassis taking place through the cavity shielding The same grounding/shielding precaution applies to the jack socket: All cheap ones have non-isolating all-metal chassis.
Having such a socket mounted onto cavity shielding + running a shielded wire from vol potmeter to the socket almost certainly will create a ground-loop. Better use an isolated jack socket - and a shielded wire ;)

Great pickup wire color code chart, Kim :bow:
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 25, 2018, 05:13:06 AM
Is the pot chassis tied to ground?

I'm such a dumb ass!  I think this is what the problem is!

I literally just took for granted the pot was grounded.  There is a good reason for this though I promise!  Normally I shield all my guitars, so no need to have a ground chassis wire because the pot is screwed down to the shielding and therefore correctly grounded.  This guitar has no shielding (yet) so the chassis still needs it's ground wire!

I will report back once I have grounded the chassis.

@Kim  Yeah man I'm all good with the dimarzio colour scheme.  As I mentioned the switch actually functions correctly, it's just I can't touch it without a noise happening, but when I let go it's ok.  Unless it's all the way down in which case there is a noise.

@Van Sinn  yeah you're right.  Normally I do shield the guitars, I just haven't bothered with this.  Had I bothered there wouldn't be an issue because the pot would be grounded by being screwed down to the shielding (I use copper tape).  As for ground loops, well schooled on this when it come to inside a guitar electrics, been doing it for years.

I'm positive MJMP has got the answer here, the pot has no chassis wire.  Already explained above though.  I shall report back!
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on November 26, 2018, 08:07:59 AM
ok keep us updated!
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 28, 2018, 02:41:28 AM
That sorted the noise issue with me touching the Strings, but I must have damaged the pot some how?  I feel like I may have done something to it when I put the knob back on as it was really tight and I had to push very hard to get it down to the bottom.  Would this have caused damage?  So basically it crackles when I turn it the same way it would if say the pot needed cleaned (at least that’s how it sounds to me).  So I don’t know whether to use cleaner or replace the dam thing again (it is brand new).

What do you think?

But the initial noise of my touching the metal knob has been fixed so that’s something at least.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on November 28, 2018, 08:02:37 AM
I think you damaged it and it will need replacing.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 28, 2018, 10:36:32 AM
How can I push the knob on without damaging the pot?  If I lubricate the knurled bit of the pot then the knob will come off to easy  and could get lost so I'm reluctant to do that.

Any ideas?  I've always not known a safe way to put back knobs onto the pot shaft.  I think pushing the knob back on has damaged the pot internally.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on November 28, 2018, 01:42:10 PM
From what you tell it looks that way, it can happen sometimes. When you turn it do you feel some mechanical abnormalities?
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 28, 2018, 01:59:32 PM
Ok it's not the pot.

So the noise is not crackling like a worn pot.  When I take my hands of the strings and only touch the knob I get crackles touching it and it gets worse when I move it from 0 to 10.  When I put my hands on the strings and touch the knob it doesn't seem so severe and also I can turn it without much noise.

What the hell?  It's grounded.  See photo.

I'll try move the ground wire to the actual pot part of the push/pull as currently it's on tab which to me looks as though it's specifically for grounding.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on November 29, 2018, 03:01:21 AM
Moved it and there is no difference.  WTH is going on???

Really don't want to replace the whole goddam push/pull AGAIN.

There is no weird mechanical feeling when turning the knob, it's as smooth as butter to turn.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on December 02, 2018, 06:14:05 AM
Should I replace the whole thing at then jump?
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on December 03, 2018, 09:07:34 AM
I would first take a multimeter and check all my connections with an ohm meter. One pin on the ground of the jack.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on December 03, 2018, 11:31:57 AM
Like to make sure I get the humbuckers full ohm reading and split reading?

I have done this but I will try again.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MarshallJMP on December 03, 2018, 02:25:57 PM
No just checking if everything is grounded, like the pots chassis, bridge etc..
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on December 06, 2018, 04:21:16 AM
So I swapped it out and used another push pull.

Same shit.  It makes noise when you turn it and have no hands on the strings.  But when you have your hand on the strings and touch it and turn it it more or less makes no noise.  Seems to function normally apart from this.

No idea why it's making this noise, outside of the push pull chassis is grounded as it should be.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: MikeB on December 06, 2018, 12:02:08 PM
Hi Gerry.
I sense that you are a little frustrated here.  I think I would be too.
I'm no expert, but here's my two cents worth. If you swap out one component and the problem remains then is likely that the problem is not in that component. You have been very focussed on the pot as the source. Might be time to look elsewhere.
Mike
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: Systematic Chaos on December 06, 2018, 03:35:41 PM
This sounds all like a grounding issue....having been there and gotten that t-shirt a couple of times myself, check the grounding wire that goes to the bridge (or the lockong trem spring clamp).
If the noise goes away once you touch the strings, that part of the guitar has a grounding issue....
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on December 07, 2018, 03:16:50 AM
Hi Mike,  yes I guess you are right.  Hard to think straight when you start to get pissed of at something.  I thought the wiring was incorrect and had been searching the internet looking for other diagrams or confirmation of my own but it all seems fine.  I still don't understand why it's only tone/pushpull that this noise issue happens though this is why I concentrate on that as the problem.

HI SC, man the noise goes away when I touch the strings because the strings are grounded because they rest on the tremolo which is also grounded.  I haven't checked directly but I think touching the trem and turning the pushpull pot results in the same thing outcome as just touching the stings.

So hands on strings/trem = no noise when turning the tone push pull
No hands on anything = noisey turning on the tone push pull

will have to go back to the drawing board here.
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: rabidgerry on December 09, 2018, 12:15:20 PM
Ok so I swapped out the volume pot again (as I had also put in a 1meg pot) and this give me a chance to see all the earth wires and know for sure they were grounded.

Not one was disconnected or anything else.  And of course re-soldering the original 500k pot back in allowed me to revise each and every one so I know for sure the trem is grounded, both pickups, the volume pot, the push pull pot, the pickup selector switch.

Still the noise persists if I let go of the strings and turn the push pull.  Totally give up now, I can live with it I guess but ideally I would like to know why this is happening?
Title: Re: 2 Humbuckers, 1 Volume, 1 Tone/push pull coil split - Help Please!
Post by: Systematic Chaos on December 09, 2018, 05:37:59 PM
Bummer...stuff like this always drives me nuts as well....

To rule out the obvious...did you try/check hooking up either one of the pups on its own to the vol pot, just to make sure the pup is not damaged?
Bridge pup - vol - tone: check
neck-pup - vol - tone: check

Add the components (pots, switch, 2nd pup) one at a time until the noise appears and you'll have your culprit.