This article saves me

[Bantar]

I was researching rf interference and pickup hum on the bridge pickup of my project Essence when I stumbled upon this article on a similar sounding issue.

https://club.alembic.com/index.php?topic=25366.msg254607#msg254607

When I tried swapping leads on both pickups, voila!  The neck pup suddenly got the symptoms and the bridge pup was cured!  Solution, change the neck pickup back to its prior configuration. So either the mxy and axy pups are internally opposite configuration, or the Essence pre, which has the pup connectors side by side, is not directly compatible.  That sounds like a question for Mica.

Cheers

[edwardofhuncote]

I experienced a similar issue recently with my SuperTele project. Somehow, when reconnecting the pickup leads to the connectors after fishing the leads through the wiring channel, careful as I was, I somehow got them reversed. This resulted in not only a noise problem, but also a weird switching thing. The correctly wired bridge pickup when solo'd sounded fantastic, but the neck pickup was noisy and picking up an AM radio station. Weirder still, when the selector was in the middle position for bridge and neck pickups to be on, they were trying to cancel each other. I went back and looked at at my pictures and sure enough... I had the leads backward.


Easy fix. I was embarrassed to tell Mica... but I had to fink on myself for that one. 

[Bantar]

But these Alembic pups came to me with connectors on them, and they are a braided shield and hot wire, so it wouldn't seem to be caused by a simple mistake by a layman.

[David Houck]

Could one of the connectors be upside down?

[Bantar]

OMG, as you can see in the attached photo, the lead polarities in the plugs are in fact the same.   This means that the bridge Pup leads (on the bottom) came to me reversed.  Seems unlikely this was an issue with the preamp or pickup per se, but that someone attached the wires to the connector backwards.  Not sure how this happened but another mystery solved!  Thank you!

[David Houck]

This post by Mica on modular connectors might be helpful:

https://club.alembic.com/index.php?topic=209.0

[Bantar]

Yes,  thank you.  I referred to similar info to change the lead positions in the connectors. The mystery is how the neck pickup got setup incorrectly in the first place. Maybe in a previous life that pickup was connected to a preamp that takes leads in opposite positions, if such a thing exists. Maybe a different brand, or just a faux paux by some previous owner. Who knows.  But thank you, the discussion had been very helpful!

[edwardofhuncote]

My guess is; in a previous life it encountered a Wire Dunce either on my level, or close to it, who attached the connector to the leads backwards. Easier done, than said for guys like us.