Trapeze tailpiece conversion

12stringaddict · #1 10-09-2022, 08:12 PM

Has anyone ever converted bridge pins to a trapeze tail-piece on an acoustic guitar?

RogerHaggstrom · #2 10-10-2022, 05:12 AM

No, I can't see why you should do that. Pin bridges sound so much better. I have changed the bridge style the other way around plenty of times.

redir · #3 10-10-2022, 07:03 AM

Agreeing with Roger here, a guitar that is designed to have a tail piece will be built different then one with a pinned bridge so you might not get a very pleasant tone if you do such a conversion.

What do you have in mind wanting to do this?

12stringaddict · #4 10-10-2022, 07:22 AM

I have a 12 string with some slight bellying and I was thinking about ways to get the top more flat. I want to go to the guitar store to get a humidifier to re-hydrate the guitar. My local tech said that solid wood tops have a memory and can sink down a little bit after being hydrated. I have it tuned down a half step and use a capo. I did tune it down a whole step, but it didn't play or sound as nice.

ChrisN · #5 10-10-2022, 09:41 AM

Quote:

Originally Posted by 12stringaddict

I have a 12 string with some slight bellying and I was thinking about ways to get the top more flat. I want to go to the guitar store to get a humidifier to re-hydrate the guitar. My local tech said that solid wood tops have a memory and can sink down a little bit after being hydrated. I have it tuned down a half step and use a capo. I did tune it down a whole step, but it didn't play or sound as nice.

Opinions vary, but I solved that issue on my '70s Japanese OM Student Martin knockoff by installing a Bridge Doctor.

If yours is an expensive guitar that might lose value with such a modification that requires you to drill a hole in the bridge, and through the top, then pass, but otherwise, my own experience suggests it's worth a try. Took my top to flat (no belly in front of the bridge, no hump behind it), lowered the action (due to lowering the back of the bridge via the Bridge Doctor), and the tone remains the same (quite wonderful, considering the price point, or not). Note that the tone is impacted by the BD's final adjustment, to which issue the website is unspecific. There's a sweet spot for the tension, once the top's been restored to flat.

EDIT: I should have mentioned that I added the BD about 6 years ago now, and the top's not moved, bridge is level, etc. I'd do it again. My particular guitar was built very lightly, compared to my more modern mid-priced models.

RogerHaggstrom · #6 10-10-2022, 10:15 AM

So, it's a 12 string with a pin bridge and problems.

I have seen many "conversions" from pin bridge to a tailpiece as a simple method to fix a problem. Often the pin bridge is still in place and the tailpiece slapped on. With a cheap guitar and playing the blues, that's not a bad idea, it sure looks cool :-) I don't like the sound from a tailpiece guitar and would never do a conversion to a tailpiece the proper way, but as a quick fix it sure works - for a while. With a 12 string, a tailpiece will actually sound better than on a regular guitar. With a 12 string, it's all strings with jingle & jangle and no need for great sustain or tone!

When I do the opposite, convert from a tailpiece to a pin bridge, I also change the bracing of the top. The result is always a much better sounding guitar.

JonWint · #7 10-10-2022, 11:17 AM

Quote:

Originally Posted by 12stringaddict

I have a 12 string with some slight bellying and I was thinking about ways to get the top more flat.

"Flat tops" aren't flat.

How much belly? Put straight edge parallel to the bridge. Measure side gaps between straight edge and the top at the edge binding both sides.

How much bridge rotation from the top?

Guitar make/model?

12stringaddict · #8 10-10-2022, 04:26 PM

I don't know what bridge rotation is, but it is a rare 1983 Yamaha FG-612s. There is about 4 millimeters(0.15748 of an inch) of bellying. I was planning on re- hydrating the guitar and hoping for the best.

JonWint · #9 10-10-2022, 06:03 PM

That's a healthy belly. 0.25" is generally considered the upper limit.

Bruce Sexauer · #10 10-10-2022, 07:43 PM

FYI: Hydrating a guitar top will usually increase its belly, while de-hydrating it should decrease belly. The top of the guitar in question sounds like its belly is due to string tension and resulting torsional stress, which is normal and desirable, up to a point.

As previous pointed out, guitar structure is conceptually different for the torsional forces exerted by a pin bridge than it is for the press exerted by a tail piece system: Don't do it.

12stringaddict · #11 10-10-2022, 08:04 PM

I only wanted to know if it was possible, only thinking after I had already posted that the structure would be different. I was planning on hydrating and leaving the guitar alone with loose strings in its case for a week or so. Somebody told me to put a weight on the top but I don't want to damage anything.