Replies to This Discussion

Permalink Reply by The Phrygian Kid on April 6, 2012 at 6:31pm

Try it. Don't confuse discussions about taming the top end or reducing unwanted handling noise with discussions re avoiding feedback tho...
If your amp is facing you and it's up loud it is going to feedback, it's inevitable.

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Permalink Reply by dave price on April 6, 2012 at 7:39pm

I agree with the Phrygian Kid Amp placement is a major cause of feedback. Piezo pickups are very efficient giving a high output, and a lot of people make the mistake of connecting them to a regular guitar amp designed to work with magnetic pickups. These amps have high gain input stages that will go into oscillation ( feedback) when matched with the wrong pickup type.

When you build your CBG do you intend to connect the pickup directly to your amp, via passive volume / tone controls, or active volume / tone control.

If you connect directly with no control on the CBG I suggest you connect a 100 K ohm resistor in parallel with the piezo.

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Permalink Reply by Roger Morin on April 6, 2012 at 7:48pm

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.

 

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Permalink Reply by Darren Wolbold on April 21, 2012 at 12:05am

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/

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Permalink Reply by JoeRocket2 on April 21, 2012 at 1:03pm

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.

 

 

 

 

 

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Permalink Reply by Maddog on April 30, 2012 at 1:14am

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!

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Permalink Reply by Darren Wolbold on April 30, 2012 at 2:30am

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

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Permalink Reply by Richard G Caudill on April 30, 2012 at 4:56pm

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

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Permalink Reply by Eric E Smith on June 21, 2013 at 7:46am

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.

https://api.ning.com/files/xOZw5uzSvCDsOG91HeoUgat8BStgRmUJT3WjY*pD...

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Permalink Reply by Dan Sleep on June 21, 2013 at 8:02am

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.

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Permalink Reply by Eric E Smith on June 21, 2013 at 8:05am

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.

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Permalink Reply by Dan Sleep on June 21, 2013 at 8:30am

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.

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