Replies to This Discussion

Permalink Reply by Seasick Mick on January 10, 2015 at 8:21am

Hullo Dave.I'm by no means an authority on Piezo's but as far as I'm aware,size doesn't matter (thank God!).It sounds as if you haven't shielded the piezo yet,so make sure you do that or it will always sound tinny and harsh.....

Permalink Reply by smilingdog1 on January 10, 2015 at 8:55am

Traditionally, I place them under the bridge glued against the box lid. The amp you use also is a factor in sound quality.

Permalink Reply by Marcus Darwell on January 10, 2015 at 10:26am

Size don't count at all. I also don't mount them on the box lid anymore.....to much external noise gets picked up. Assuming you have a gap between the lid and your neck (which I think you should but opinions may vary) I counter sink a shallow hole in the neck under the bridge and mount it there....you don't have to be too close to the bridge but not more than an inch or so away. I use either thick double sided tape or hot glue to hold the piezo in place. This way you pick up the string vibes and not too much interference.

Permalink Reply by Servaas (Der Groovemeister) on January 10, 2015 at 11:25am

A piezo will often sound tinny if you don't use a preamp. It's because of the impedance mismatch between piezo and amp. Lookup the Tillman preamp for example. Some tube amps don't mind the mismatch and therefore won't need a preamp.

Permalink Reply by Slow Slough Guitars on January 10, 2015 at 12:23pm

A preamp is essential for a better sound out of a piezo. I have a Behringer PB100 pedal type preamp that I use. Costs about $25 from Amazon and runs on a 9v so you can use it busking. I've also used the type that mounts on the git and had satisfactory results. Disc placement as has been pointed out can make a big difference. Most people like some separation between the disc and your lid, whether it's gobs of hot glue, thick double sided tape, or as Marcus suggested recessing it in the neck (hadn't thought of that, I might try that one) direct contact will have a price to pay. I have one that is in direct contact with the license plate and it sounds gritty, grimy, and dirty. The sound is breaking up before it even gets to the amp. Just how I planned it. But the other side of it is that every time you touch it you make a sound with it. So it lacks any control at all.

Permalink Reply by Slow Slough Guitars on January 10, 2015 at 12:25pm

Another hint is to mount it on the side of your lowest tone string. For most builders it's the top string. That makes the bass side the dominant.

Permalink Reply by Henry S on March 25, 2015 at 7:05am

I'm going to keep my first CBG pretty simple and go with a piezo (or two) and probably a Tillman preamp mounted internally.  I've seen several articles - videos on potting the piezo between wood wafers and hot glue and one guy even uses a pop bottle cap with the piezo potted on hot glue. Anyone haves any direct experience on using potted vs non-potted piezos ?

Thanks

Permalink Reply by Gary W aka Rev. Bluejeans on April 23, 2015 at 9:30am

Henry - I saw a Justin Johnson video describing the process to 'pot' the disk in a bottle cap as you describe - Justin commented that he liked the end result a lot.  I've 'glopped' hot melt glue over and under piezos in a few of my builds, and it does seem less tinny.  But my next piezo plan is to hot melt pot one into a cap of some sort.   The suggestions about mounting it near the bass side of the bridge also seems to be good advice in my experience.

Permalink Reply by Henry S on April 26, 2015 at 8:50am

Yep - still working on my first build I plant to use 2 piezos that are switch selectable - either one or the other: One will be mounted in the glued bottle cap under the bass string to the box lid, other will be counter sunk into the neck under the bridge and potted with hot glue. Which ever is selected will go through a Tillman preamp that is mounted in the CBG. 

Permalink Reply by Gary W aka Rev. Bluejeans on April 27, 2015 at 9:47am

Cool idea - be sure to update here on how it turns out!  Maybe one or the other becomes your preferred method...