Piezo Elements

[B.Flat]

Hi All.
I need to repair an early 80's YAMAHA piezo bridge. However I do not know where to find the small piezo elements I need.
Any suggestions ?
The attached photos show the (uncleaned!!) bridge.
You can see the white wire entering the bridge saddle, and in the lower photo you can see the radius-ended recess where the piezo element goes. It is about 3mm wide and 3mm deep, 2mm high. A small grub screw holds the element in place. The bass is MOTION LB2 which I am hoping to restore,
all advice gratefully received

 

[bholder]

I wonder if the Graphtech / Ghost folks might have something that fits?

 

[bholder]

Doesn't look likely. I think your best bet is to replace the entire bridge.

 

[Killing Floor]

Not being sassy. What makes you think the piezoelectric sensor needs to be replaced? It’s ok, I’m a mechanical engineer so I’m comfortable saying this, a piezoelectric crystal is basically a rock. You can’t damage it by “bass” pressure. Maybe all it needs is a solder refresh.

 

[bholder]

Maybe one of these types could be fit in there?
Saddles for BASS

 

[B.Flat]

Thanks for the replies.
I would really like to save this original bridge, the whole thing is a restoration project.
The previous owner has messed about with the saddles. The G string did not work at all and when I tried to release the other elements to get an idea of what I would be looking for, I discovered that whatever was in there had been glued in with superglue or epoxy. Consequently the elements were destroyed in trying o remove them.
I do not know if there are different types for different frequencies, or if size matters. I suppose I am hoping for an expert in the field to answer, or someone who may have already gone down the road I am headed on.
In all respects this bass is virtually identical to the TRB 4P I should never have sold!

 

[thewildest]

For some reason I can’t see any piezo elements there. My Yamaha TRB-6P has small square piezos that go underneath the brass saddle. The saddle passes the vibration down the piezo, that is secured to the saddle with some minute screws.

Does the bass have any of the original piezo elements you could take a photo of?

 

[Wasnex]

If I remember correctly, @DoubleMIDI has significant technical knowledge on piezos.

AFAIK, you should be able to just use a suitable piezo element that fits. You don't need a piezo element that is specifically built to function as a pickup on an instrument. That's not to say, that some options would not be better choices than others.

Here is an article from a company that offers small leaded piezo spheres (for medical purposes?):
Piezoelectric Spheres and Hemispheres in Miniature Format (physikinstrumente.com)
Miniaturized Piezo Ceramics (piceramic.com)

"Piezo micro spheres are available with outer diameters as low as 2mm and wall thickness as thin as 200µm." Should be small enough, but I suspect these may be expensive.

Surely there are other companies that make similar products that would be suitable for your project. You just have to find a suitable product with an acceptable price.

I found several mentions that used the term "bimorphous piezo element" in relation to Yamaha basses. A google search of the term was not helpful.

Quite a few companies make pickups with piezos mounted in the individual saddle pieces. Perhaps calling some of the companies would be helpful.

If Yamaha offers(ed) replacement parts, my guess is they would sell the entire saddle; rather than the piezo elements.

 

[B.Flat]

Thanks for your replies, thewildest and Wasnex. The bridge is a more complicated design than the TRB version.
As I explained, the elements were encased in epoxy glue and I didn't find anything recognizable as an element in the debris but there must have been something in there because the E, A, & D worked. The G, which did not work had a very small rectangular tab, which really looked like a bit of paper. I was expecting to find a small and rigid item, as I would expect a crystal to be.
I will follow up on your info and advice Wasnex, thank you.