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PostPosted: Thu Feb 12, 2009 10:59 pm 
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Koa
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I am just working on an Ibanez acoustic with a piezo pickup that is dead on the low e a and d strings. It seems to be working fine on the high 3 strings. Anyone have any good tricks for trouble shooting?

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PostPosted: Thu Feb 12, 2009 11:09 pm 
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Koa
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Usually with an under saddle pup, if you have a dropout it is from the saddle or saddle slot no being flat. Remove the strings and saddle, plug the guitar in and tap (lightly) on the pickup strip and make sure it is active along the whole length. If it is, check the saddle and slot for debris. next, check for a flat saddle and slot. Hopefully, you just have an uneven saddle.

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PostPosted: Fri Feb 13, 2009 6:42 am 
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Koa
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Thanks Joe. I reflattened the saddle. The slot is hard to tell if it is flat. I will try tapping the pickup itself to see if it has some dead spots. I guess I am not exactually sure how the first half could die and the rest still work?!? Does anyone know of a way to check if the bridge slot is flat the bottom?

Brad

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PostPosted: Fri Feb 13, 2009 7:42 am 
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Brad .. you need a short straight edge .. the one end of the SM action gauge would work if you have one .. even a bus card might do the trick.

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PostPosted: Fri Feb 13, 2009 9:08 am 
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Brad Way wrote:
Thanks Joe. I reflattened the saddle. The slot is hard to tell if it is flat. I will try tapping the pickup itself to see if it has some dead spots. I guess I am not exactually sure how the first half could die and the rest still work?!? Does anyone know of a way to check if the bridge slot is flat the bottom?

Brad


That's what I'd do, check the pickup itself. You might also google, "John Zyla clay method"

I stopped using USTs almost a decade ago, between ugly tone & string balance issues.

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PostPosted: Fri Feb 13, 2009 11:58 am 
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Koa
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Brad, physically, there should be no reason why 1/2 the piezo would still be putting out while the ohther half was not. Worst case, you tear the film between the conductors which changes the output of the overall pickup - similar to cracking a piezo ceramic material...Given that UTST's are made from a plastic, I really don't think that is a problem...

Therefore, like the other guys said, something has changed in that the sound/vibration energy is no longer being transmitted at all (or efficiently) into the material in the lower strings. Like the other guys said, ensure there is good compression contact across the whole saddle slot - against the bottom of the slot and against the saddle itself. The more efficiently the energy is transferred to the sensor, the better the respsonse is going to be.

Though I have not tried it, you can try the "clay" trick, where you use modeling clay to take up the tolerance around the sensor...Fundamentally, it should work, firmly coupling the sensor the mechanically excited geometry around it...

Stephen

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PostPosted: Fri Feb 13, 2009 12:50 pm 
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It helps the electric sound with a UST to have a loose fit in the slot, and a flexible saddle material--like plastic. Not good for the acoustic sound? that's the price you pay.

I think the best way to fix a UST if it isn't responding to your first few tries is to replace it with a different kind of pickup.

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PostPosted: Fri Feb 13, 2009 4:09 pm 
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Koa
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It is fairly common, when the top of a guitar starts to pull up with age, that the bridge and therefore saddle slot will belly with it. This makes it impossible to balance the output of a UST.

I of course dont know if that is your problem, but a check of the bottom of the saddle slot like Tony said is in order.

The solution, if that is the problem, is to re-rout the saddle slot, flattening the bottom.

I am just throwing this out there, because it is a fairly common cause of balance issues with USTs.

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PostPosted: Fri Feb 13, 2009 6:38 pm 
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Koa
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[quote="jordan aceto"]It is fairly common, when the top of a guitar starts to pull up with age, that the bridge and therefore saddle slot will belly with it. This makes it impossible to balance the output of a UST.quote]

Ironically the guitar is fairly new and there also is some sort of wooden bridge support thing (factory installed) under the bridge that keeps the top from flexing. I am going to try checking the flatness of the slot again and see how that works.

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