I have an Epiphone doubleneck (The "Stairway" thingy).

I would love to add a piezo bridge on the 12 string, but I can't find anyone selling a tuneomatic bridge with 12 string piezo loaded saddles. Logic tells me that it should be possible to simply buy a 6 string Fishman Powerbridge or similar, file the saddles flat, recut them for a 12 string and raise the whole bridge unit to compensate. However, since these things aren't cheap is this an option or would filing the saddles damage the piezos? Do the piezo pieces sit inside the saddles or are they simply stuck to the bottom to pick up the vibrations in a similar way to acoustic guitar piezo wire?

I've not tried this, and it sounds... 'interesting'...

So I'm kinda thinking out loud here...

piezo's tend to come in two varieties. Individual crystals (either with separate two wire connections for each or layered between two 'terminal' strips) or in a film between two conductors. And I can conceive of ways of making both types in an individual saddle. My instinct is that the easiest way to make an individual piezo saddle would be to embed a crystal with a two wire connection, purely as this is how a lot of mandolin/violin/archtop guitar piezo bridges are made. If you can source a piezo crystal with a two wire connection, those are idiot simple to build. Just drill a hole, fill it with epoxy, and push the crystal in so the leads are sticking out.

However, I don't know how the individual saddles from Fishman, Graphtech, Schaller, etc are made. But if I was looking to do this myself, there are two approaches I would consider. The first is also the cheapest, I would write a polite email to tech support at those companies, explain that I wanted to know whether it was OK to reshape the saddles, get their interest by explaining that I wanted to do it because I was considering a piezo bridge for a twelve string, and then ask if they had any drawings showing the internal construction that would help me. You would be amazed at how helpful these guys can be, especially when you set them an interesting challenge

Second option would be to buy a single replacement saddle for each one I was considering and then carefully destroy it with files/scalpels/hammers to work out for myself how it was constructed. Then make a scale drawing of it's construction and work out if there was enough leeway to reshape for a 12-string.

I prefer the first option for two reasons. Partly because it's cheaper, but also because there is a chance that they might come back and offer a set of unshaped saddles pulled from the production line as a solution. And then tell you how they shape them themselves.

A 3rd alternative would be to find a supplier of tiny piezo crystals with a thin two wire cable connected. Get 6 of them, and then drill a small hole in each existing saddle and carefully epoxy them in place.

But however you go about it, I would be interested to hear what you discover.

Andy

--------------------
When the going gets weird, the Weird turn Pro.

As an alternative, would a Roland gk3 pickup/guitar synth be viable? Yes it's digital but you would get a shed load of other sounds?

There are cheaper versions of the Fishman bridge out there, I think Axes R us sell one for about £60? Might be a good first step, and IIRC someone here fitted one with a small preamp and it sounded pretty good.

The GK3 I don't think would track all 12 strings well, and the extra body "air" could well cause problems tracking. It was bad enough on my Aria TA semi.

Hewesy

I like Andy's idea of harnessing the curiosity/goodwill of the companies.

Another, much simpler idea although you might consider it a bit of a cop out would be to replace the tune-o-matic with a hardwood bridge to slip over the mounting posts. A wide saddle would allow adjustment in the usual acoustic way and a single film strip pickup such as the Headway Snake would ensure even response.

I have this arrangement on an archtop and it works well. Admittedly it is a six string and I'm maybe not as handy with the breadknife as others.

--------------------
Ohm's Law states, "Your PA isn't as powerful as you think it is".

I dropped Fishman an E-mail a while back and their reaction was a fairly blank "sorry we don't make 12 string bridges like this". I have e-mailed Schaller who make something similiar and I will be asking LR Baggs as well. So I will keep you informed on the responses.

As for the GR55 suggestion, I also agree that that the synth will probably struggle to track the notes properly and since I already have a GK2 synth pick up linked to a GR20 synth on the six string neck of the Epiphone, I don't really want to spend any more money on another synth (and the GR55 isn't cheap - although it is quite appealing).

The Schaller version of the Tune-o-matic piezo is about £65 and my initial thoughts are to wait and see what they say and may be go for one and file it (unless they can do a custom job for me). It is a fair bit of money to waste messing up a bridge in an experiment, but it is a lot cheaper than the Fishman and I can't think that it will be that much of a problem providing that I don't get too "physical" with it.