I recently purchased a kit guitar off Ebay that has a double neck. One is acoustic and the other electric. The person who previously owned the guitar wired the two together at the 1/4 inch jack using a two prong jack and not the three prong for the piezo pick-up. To make a long story short, the piezo didn't work. I replaced the pre amp piezo pick up and wired everything to the new three prong jack, but I can't use the pick-ups separately and if I play awhile on just the bridge humbucker, the sound slowly fades out until I pull the cord out of the jack and put it back in? (resistance building) Please direct me to a wiring diagram that may work. Thank you!!!!!!
Hi Brad. If you have a close-up photo of the setup that would help.
There are lots of ways to wire mags and piezo to a jack. For the most versatility put a 3-way switch in the mix, which will allow you to choose between the mag, piezo or a mix of the two. But since your piezo is pre-amped there could be a grounding problem in the mix... so I'm thinking the 3-way switch is one way to solve that.
Can't tell for sure though without a photo of how it's set up now... or a drawn wiring diagram.
Thank you Wayfinder! picture a Les Paul with typical wiring and an Ovation electric/acoustic joined together at the 1/4 inch jack. I kept the 3 tab jack as it is necessary to turn on/off the piezo pre-amp. How would I incorporate a 3-way to separate the two?
There are a couple of ways to add a 3-way switch. Probably one of the easiest is to run either the positive or ground wires of the pickups to the 3-way and then to your controls or jack. You just need to run one wire from each pickup (the other wire runs straight to the volume/jack).
For example, if you were to run the pickup positive wire to the 3-way, you'd put the mags on one side, the piezo on the other side and an out-wire running to the positive input of the volume or jack.
Here's a diagram of how a typical 3-way works. In your case you'd put the mags on the "neck" side and the piezo on the "bridge" side:
If you were to use a 5-way switch instead of a 3-way, you could separate the mags as well and be able to choose between the neck mag, bridge mag and piezo.
If you hook up a switch and find you're still having interference between the pickups, change which wires you have hooked up to the switch (ie, if you hooked positives into the 3-way use the grounds instead).
Follow-up Brad: I haven't tried this yet but have been meaning to. Probably would work, especially if you're incorporating a 3-way switch. You might be able to run your mags to the preamp as well. If it has volume and tone built in like a lot of preamps do, that would let you control the sound of your pickups all from one device. It's all a matter of experimenting to see what works. Failure is just step closer to success. : )
Wayfinder, I can't thank you enough!! I'm out to purchase a new 3 way and will keep you abreast of what transpires.
You're most welcome! Will look forward to hearing of the results. : )
Added the new 3 way yesterday and everything is working well. I was limited on where to install it as the guitar had been finished, but it worked out well in the middle, between the volume and tone knobs. The bridge pick-up is still crapping out once and awhile, but I think that is was damaged during prior installation--Thanks again Wayfinder!!
Sure thing! Glad to hear you had success on that. Sounds like you have a loose wire on the bridge mag. Might check and see if it needs / can be re-soldered.
Wayfinder, after checking all wiring (done very poorly) I found that they had used a Seymour Duncan 4 wire pickup and had, per the Seymour Duncan diagrams, reversed the black and green leads on the power pot. I wired and soldered all connections, but pickup is totally dead. I believe I will purchase new POT's for power and tone, new wire and maybe a new pickup after I take it out and check it over. It's going to be an expensive tomorrow!
Thanks for the advise. This guitar appears to be of Asian decent and not the best POT's and wire were used. It looks like I could have a few cold solder joints to tend with. I figure I will just start from scratch and check my work as I go.
Asian pots are known to be well... cheap. If you decide to replace the pots, be sure spray the insides with a quality electrical anti-corrosion coating. Should be available at local electronics stores or on Amazon. Also very good advice by Ted. Wiring pickups directly to the jack is an excellent performance test that bypasses the pots.