Humbucker pickup --> fuzz face clone interaction

[bipedal]

More of a pickup-wiring question than a pedal-build question, but here goes:

One of my guitars is a Tele with a single coil p/u in the neck position and a Seymour Duncan Little '59 humbucker in the bridge position; it has a 3-position selector switch.  I've been happy with the bridge p/u and neck p/u sounds from the guitar, but the middle position (combo of neck + bridge) was always a bit quieter and mellower than the other two positions, so it was rarely used.

As an experiment this past weekend, I swapped the lead connections coming from the humbucker – so black lead now goes to selector switch and white lead goes to ground instead of the (original) opposite arrangement.

This simple wiring change seemed to remedy the original problem – the guitar's output level now seems equivalent in the bridge, bridge + neck, and neck positions, and the bridge + neck position offers a nice balance of tonal characteristics from each pickup...  Great!

except when playing through my (ge) Fuzz Face clone.  With the FF, the guitar's neck and middle positions sound fine, but the humbucker on its own sounds noticeably thinner and quieter.  (The FF works normally with my Strat, and had sounded fine with the Tele's humbucker in the original wiring configuration.)

I did not notice this tendency through other pedals, including my TS-808, Crank, Tremulous Lune, or Phase 90, or when the guitar was plugged straight into my amp – everything sounds as expected in all three pickup selector positions.

So, reversing the pickup leads mostly worked, but something's up with the humbucker-only signal being seen by the Fuzz Face...

Any thoughts on what could be causing this?  I suspect the answer will be immediately obvious to many, but I'm stumped.   

- Jay

[Steben]

Could you draw a explanatory wiring schematic?

I suspect impedance tricks...
A large impedance hump won't affect a decent guitar amplifier that much.
A fuzz face however is very sensitive to impedance differences...

[MikeH]

Sounds to me like your pickups were out of phase.  Not sure about the FF issue though.