I am currently building my 1st CBG and am planning to add a piezo pickup. I have read a bunch about piezos feeding back & what can be done to reduce it.
Would it be feasable to use a small circle of Dynamat rubberized audio sound dampening material attached to the back of the piezo, or covering/doming the back side but not touching it?
Seems like this would prevent sound waves from reaching the back side of the piezo which may help reduce feedback...maybe I'm way off base though. My concern is that it may interfere with the effectiveness of the piezo in some way. Any thoughts?
Thanks for your help, Joe
Jay at tiny guitars makes his own bridge pickup with 2 20 mm piezo dishs on the bottom of the bridge held buy hot glue. I have owned a few of his builds that have that type of bridge pickup combo, never any feed back nomatter what amp I use.
I would go with two piezos wired in parallel this helps with the impedance matching to your amp.
I also glue the disks copper side down to the neck rather than the body and I also then glue a thin bit of wood over them covering the white crystal as best I can
All this seams to help a lot with feedback and makes the guitar viable for use on stage with a big PA
It depends what your using the guitar for really if you just noodling at home on a 5 watt amp you might not need to worry as much as if say you were using a marshal head double stacked on a 10 k rig every night on stage
check my blog out http://darrenscigarboxguitars.blogspot.co.uk/
Thanks for all the replys. I'm just fooling around at home & plan to build a 5-7 watt amp at some point...doubt I'd ever use anything larger. I'll probably be ordering a CB Gitty dual piezo setup w/passive vol pot...or something similarly simply to begin with.
Great thread, I just finished my second build and went with a single piezo disc (first build has a coil) and I do get humming when hooked into my big Fender amp. Plugged it into my little cigar box amp and the humming goes away so when I read what Dave said about big amps it all made sense, I started the 3rd, 4th, 5th and 6th builds (this is addictive) and I am going with parallel dual piezos, one with a coil and one with a rod piezo and see what goes. I'll let ya know. Thanks!
Funny enough I just bought a fender type switch and volume and tone plate going to maybe try some switch shinangins ,
maybe some thing a bit off the wall
one pick uo on a primative resonator and may be a parallel pair in the neck
as I have been making guitars like this already
hopfully I will post it I eventually get round to it
In the mean time I have some new designs to be making
My best ran 2 piezo in parrallel ,, embed em heavy in silicone or hot glue ,, metal side toward bridge ,,, that has cured all the ffedbacks i had ,, I use a Micro cube and a peavy rave 150
Yeah, I know that this is an older thread and all, but I am having a heck of a time with this issue.
I just finished my very first CBG, heck it's the first that I have actually seen for that matter, and may having all kinds of issues with peizo feedback.
Here are the basic plans that I followed and they really don't address the issue at all.
Piezos are screechy to begin with. You need to isolate the disc so that the sound waves coming from the amp have a hard time getting to the piezo disc. I glue mine to the underside of the lid with hot glue, and then smother the entire disc with hot glue to help insulate it. As already mentioned, they are prone to feedback to begin with, so all you can really do is tame them down a bit.
That is why some folks embed them inside a bridge/saddle so they are surrounded by wood on all sides.
On top of all of this, the piezo has to be mounted to the side of the neck and really doesn't pick up all that much.
If it doesn't pick up that much, then you are probably cranking the volume up, which makes it feed back.
Why can't you mount it to the under side of the lid? You should have it attached to the part of the guitar that vibrates the most, which should be the lid.