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benmandv
04-27-2011, 06:43 PM
Hi there,

I have a shadow nanomag pickup with soundhole preamp in my guitar, I also have a K+K pure mini which I want to install into my guitar, and I want both pick ups to be wired as stereo trs.

The problem is the nanomag has one more wire than I thought it would, it has a red, white, and ground, I believe this is a balanced output, correct me if I'm wrong?

How would I wire both pickups to a stereo trs endpin jack? I understand how to wire normal mono connections to stereo but the extra wire has confused me!

Any help would be much appreciated!

Cheers
Ben

BTF
04-27-2011, 06:57 PM
If the Nanomag is battery operated, this extra wire is probably the power supply ground wire which when grounded turns on the active circuitry. I don't know this pickup, but a three-wire assembly is usually 1)Output, 2) Signal ground and 3)Power supply ground (this wire usually goes to the ring connection of a stereo jack. When the plug is inserted into the jack, the sleeve on a mono 1/4" plug joins the two grounds together and the active circuitry turns on, ensuring the battery is only drained when a plug is inserted into the jack).

Hope this helps. Perhaps someone familiar with this pickup can say for sure.

Regards, BTF.

jhchang
04-28-2011, 03:35 PM
You also need to be careful about the phase issue. Two signals can cancel each other out if out-of-phase.

benmandv
04-28-2011, 06:52 PM
Cheers for the help guys, got it wired up and working!

babyrockstar
05-01-2011, 08:44 PM
Nice you fixed it on your own, I also had the same problem before and I tried to experiment a little and it works.

guitaniac
05-02-2011, 07:54 AM
benmandv,

I believe that you need a stereo jack with three contact tabs (four total contacts, including the ground contact) to do this right. The battery lead is wired to the longest contact tab (the shortest tab being the tip contact and the medium length tab being the ring contact). When a plug is in the jack, the long contact tab is shorted to ground and the power circuit is completed. When no plug is in the jack, the power circuit is open and the battery is conserved.

If you have a stereo jack with only two contact tabs (tip and ring), and you've wired the battery lead to ground, then the power circuit will be on constantly unless you remove the battery when the pickup isn't being used (or you insert a switch of some kind into the battery circuit).

I cases where you're wiring a single active pickup system to a stereo jack, the ring contact can act as the switch contact (presuming that you'll be inserting a mono plug into the jack).

Hope that helps,
Gary

guitaniac
05-06-2011, 08:39 AM
I came across this stereo "switching" jack on ebay yesterday. http://cgi.ebay.com/Fishman-Switchcraft-4-pin-Switching-Stereo-Endpin-Jack-/170566649715?pt=Guitar_Accessories&hash=item27b6908773

This is the kind of stereo jack that you need to handle dual sources when one or both of the sources is an active system. With this kind of jack, the longest contact tab is connected to the battery's negative lead. The shortest contact tab is the tip contact and the second shortest tab is the ring contact. The sleeve is ground.

Here's the diagram for the "switchjack" off the Fishman website:
http://www.fishman.com/files/switchjack_user_guide.pdf

Gary