Single coil pickup wire shielding Question

[tubenit]

I've got a Tele that has inexpensive (but great sounding) Alnico 2 strat pickups.  Love the tone of them.  They are pretty quiet with the 5 way switch in the 2 & 4 position given the reverse wound middle pickup.  However, still not totally quiet even in 2 & 4. 

The guitar control cavity is well shielded with copper foil and everything is grounded properly.  I also put copper foil over tape around the pickup wiring itself and grounded that. The only thing left unshielded is the wire itself from the pickup to the control cavity.

Last thing I now want to try is shielding the wiring from the pickup into the guitar control cavity.

What I don't know is should I use 2 wires with a shield around both …… OR   simply shield the "hot" wire and use the shielding itself as the ground wire?  Thoughts on a best guess approach? 

Interesting article about this idea here:  https://www.seymourduncan.com/forum/showthread.php?148600-Single-coils-why-not-use-shielded-cable

Thanks,  Jeff

[jjasilli]

I would use 2 signal leads with separate shielding.


If there are separate strips of copper tape, are they electrically connected?


Have you fully separated signal vs chassis ground?

[tubenit]

Jjasilli, 

Thanks for the advice!  Yes the strips are electrically connected and signal vs. chassis ground is separate. The guitar is already reasonably quiet for single coils, I am just trying to squeak out a little more in lessening noise.

Thanks, Jeff

[jjasilli]

I did think you had these points covered, given your expertise.  For years I've been following the guitar wiring/grounding scheme of guitarnuts.com, but their website changed sometime ago and, their wiring schemes seem to be gone.  Anyway, they recommended "mic" cable - two signal wires + outer shield - for guitar cavity wiring.  Also, larger gauge wire is better.


My experience is that all this does does improve signal to noise ratio; but there may still be some noise.  Exterior factors are the particular amp & where you stand in relation to it; fluorescent lights; dimmer switches, etc. 

[tubenit]

I used shielded two conductor wiring for the pickups.  It took me 3 hours to take the guitar apart, rewire the pickups, rewire the guitar, put the guitar together and put all the tools and solder up & test it out. 

It would be VERY easy to make a mistake and mess up a pickup with the super thin wiring used in the pickup winding. I kept wondering if I was gonna completely end up ruining a pickup. 

Fortunately, I didn't mess anything up.   

YES, the guitar is quieter.  The neck and bridge pickup are maybe 25 to 33% quieter?  The reverse middle pickup now has less then half the previous noise, maybe 25% the previous noise.  The 2 & 4 positions are totally dead quiet.  Super quiet. Easy as quiet as any of my humbucking guitars. The middle position is significantly quieter then the neck and bridge. It's almost humbucking quiet but not there as it still has some slight single coil noise. But you almost have to listen for it to notice it.

Previously, the noise in positions neck, middle and bridge were about equally single coil pickup noisey.  And despite the middle pickup being reverse would, positions 2 & 4 were still putting out more noise then humbuckers prior to this shielded wiring. 

So, I feel like it actually made a worth while and significant difference in positions 2,3 & 4.  And made a somewhat noticeable difference in positions 1 & 5.   Referring to the 5-way switch. 

There is no way that I think someone could hear the single coil noise while playing the guitar at any volume low or cranked.

Yes, I would do this again IF I had another set of single coils without shielded wiring.  I should note that the pickup windings were already wrapped with copper foil that was grounded to add shielding there.  And the cavity of the guitar was totally shielded with copper tape already also.

With respect,  Jeff

[jjasilli]

   Great report!  Thanks for this info.

[Willabe]

I should note that the pickup windings were already wrapped with copper foil that was grounded to add shielding there.

When you wrap the coil wind/shield it and ground it, did it bleed off some off the PU's output and/or hi end? 

Wouldn't it bleed off some of the coil's magnetic field? 

[jjasilli]

Copper is not magnetic so presumably it should not affect the magnetic field.  Could have a parasitic capacitance affecting hi's.  Don't know if an A/B test is practical w/ or w/o the copper shielding.  Might be worth it for noise reduction.

[Tony Bones]

There will be some eddy currents in the copper that with shave a little off the top end, but it is a small effect if the layers of copper are insulated from each other. If you try this with bare copper (or aluminum foil) it will make what is essentially a shorted turn and impact both the output and the high end. The farther from the coil the shield is the lower the influence, but this is why you don't see many single coil pickups with metal covers.

To repeat, if you wrap a layer of copper tape around the coil but don't connect the start and finish of the layer, it will affect the sound, but not a lot. It's a technique sometimes used to tame over-bright pickups.