Double Neck Guitar Electronics Connections Diagram Sought

[Sumit Simlai]

In my previous post, I had mentioned about entrusting the work of building a new double neck Hawaiian Electric Guitar to a luthier, whom I met by word of mouth. After 14 months of my last post when I said I found the guy and even mentioned as so far so good, I just returned from Kolkata to New Delhi after taking delivery of the guitar, having booked a separate seat on the plane for the instrument.

While purchasing the pickups and switches, Seymour Duncan Technical Department strongly advised me that, to get the best overall configuration and benefits of each pickup I should follow the circuit schematic of the Gibson EDS-1275 Spanish Guitar which actually would serve well for my Console Hawaiian Steel Guitar project.

That circuit employs two specific switches – one, a Switchcraft 12010X 3-way selector switch for neck selection, and the other a Switchcraft 12015X switch for pickup selection. SD even shared a pdf drawing for my convenience.

I had the following items to the luthier according to the diagram and along with copies of drawings and emails from SD:

1. Two Seymour Duncan ‘59 Model Bridge Pickups - 2-conductor humbucker
2. Two Seymour Duncan ‘59 Model Neck Pickups - 2-conductor humbucker
3. Two Seymour Duncan YJM volume control pots 500K (logarithmic / audio taper)
4. Two Seymour Duncan tone control pots 500K (linear)
5. One Switchcraft 12010X switch
6. One piece Switchcraft 12015X switch
7. One Switchcraft phono socket

The luthier constructed the guitar body out of mahogany and the overall mechanical fittings are pretty nicely done I would say.

But he screwed up badly on the electronics and never in the past 14 months, despite my enquiring almost every week, the fellow never admitted his lack of understanding of guitar electronics, the way it is done at an international level. So he ended up connecting the 12015X as a neck selector and the 12010X as a showpiece, no functionality.

As things stand now, I have to personally get involved with rectifying the guitar electronics myself. And I feel that instead of trying to figure out how to troubleshoot and end up shortening wire lengths and other goof ups, I might as well desolder everything and start afresh.

"May God give me the courage and strength to set this right." But I can't do it without help. That's for sure.

First things first, the Switchcraft switches do not come with any terminal diagrams indicating how the connections work in each of the three positions. Then I should be able to draw up a wiring diagram to match with the Gibson schematics.

I shall be more than elated and obliged, should someone be able to help me in this area.

PS: I was told by SD that guitarelectronics.com offers custom diagrams but when I perused the site, all I could find was diagrams for single neck guitars, which in any case I have from SD when I bought the pickup.

[Jeff Highland]

This may help
https://au.mouser.com/datasheet/2/393/S ... 949416.pdf Schematic in left top corner

https://au.mouser.com/datasheet/2/393/1 ... 998237.pdf Schematic mid left

The good thing about the switchcraft open switches is you can see what is connected in each of the positions if you look carefully

[Sumit Simlai]

Thanks and I have this drawing too because I had to furnish it to the luthier for making provisions in the wood and the top plate. This however does tell me anything about the connections.

[Jerry Jones]

I guess you already have this?

[Dave Grafe]

[Dave Grafe]

[Sumit Simlai]

I have been informed by various people including new tech dept staff from SD that the 5 terminal ordinary toggle is a pickup selector, not a neck selector as is wrongly depicted in the original Gibson diagram. I have an email from Gibson as well that the original diagram has this error but they were unable to find me a corrected version of that diagram..

Later SD sent me a corrected diagram. I’m attaching that here.

So your statement that Neck Switch in one side has three and on the other side has two is perhaps incorrect. It is the pickup switch which has 5 terminals.

[Sumit Simlai]

I would like to ask something here. Is it usual for a double neck steel guitar to be wired such that with one neck active, each pickup is separately controlled, which means, Bridge Pickup is controlled one set of Volume and Tone pots, and Neck pickup is controlled by the other set of Volume and Tone pots? The guitarelectronics.com and the guitarnuts2 guys tell me that the following is usual with Gibson EDS-1275:

"We looked up the original EDS1275 diagram for the 6/12 and there is one volume and tone for the front pickups (forward position of both necks) and one volume and tone for the bridge pickups (rear positions of both necks). The volumes are not for each neck. With the traditional Gibson EDS1275 setup, when you are on one neck alone, both volumes and tones control that one neck. With both necks on, turning down one volume turns down the pickups on both necks."

Any lead on this query might help me.