Hey gents -
I'm just finishing up my second build and spent a good part of the day messing about with a disc piezo. The wires that came off of them are extremely thin and today had me:
1) Installing one between 3M tape and then to the inside of the box under the low string, right below the bridge only to find I crushed the ceramic disc after pressing it between the foam tape. I read of this method on a blog...
2) Installing it in a bottle cap (looks very cool), but the solder joints on the thin piezo wire failed. Followed a YouTube video for this one (filled the cap with hot glue, etc.)
3) Tried the bottle cap method again because I liked the look of it so much, got my wiring sorted out (finally) and plugged her in, but...
Is it normal to have to really crank up the volume to get any decent sound from these pickups? I have mine mounted in the cap, surrounded with hot glue, no voids and then glued tight to the inside of the box, right below the bridge on the lowest string.
I know setups are subjective, but for comparison, my first build has a mini-humbucker and I can turn my little Fender tube amp to about 2 in the living room, v/c on the guitar full on, and she throws some good sound.
With the disc piezo, v/c full-on, I had the amp to 4 and it sounded 'ok' but kind of anemic... definitely not fired up about the sound. Also, at '4', theres noticeable hum.
Am I missing something? Expecting too much?
I'm tempted to scrap the piezo and put a mini-humbucker in there; the unfortunate part is that I put a sound hole / screen near the top front corner, so the new pickup could only go dead-centre where box art is - shame to cut that away.
If I am expecting too much from this round piezo, how does a bridge piezo compare? Can this setup be saved?
P.S. I'm running CBG 4-string Acoustic .034 - .013 with a wood bridge with bone.
Thanks Jeff - I may give that a shot.
I gave up on bottle cap piezos because the smaller peizos (20mm) aren't hot enough for my taste... You can run 2 in parallel.. I prefer 27mm discs and hot glue.
I also stopped buying cheap chinese piezos... better quality ones are on a heavier piece of brass... and are worth the money...
Maybe that's part of the problem. The piezo's I purchased are from China... so far, I'm more inclined to just set a nice pickup in there like my first build.
Thanks PA! When I tap on the bottle cap, there is definitely an audible 'thwack' (technical term). I'm suspicious of the glue in the bottle cap. For future, if I go the round piezo again, I'll grab some from CBG. Thanks for the tips on the preamp as well.
You went through the basic methods pretty well, some things to note though, normally under the bridge is 1/3 to 1/2 way down the box, with your bridge being so far to the rear, your piezo is in a very solid, less vibratic area of your sound board, and certainly will be quieting it some, though it should still be pretty loud, next for some piezo's, and i don't know why, they will work fine on one amp, and very poorly on another without pre amping. I would put some double sided tape on yours, and just move it around until it sounds best. a good way to test your current disc is, as you can open the box, just turn the volume up and tap the disc with your finger, it should be quite loud, if not you might have a wiring issue, or a bad disc, also the rod piezos for bridge mounting are quieter than the discs usually, they soak up a lot of the handling noises
Thanks Darryl. I the tap test and all was good. By the time she was taped in the box, no sound... I'll do an update below. Good to know about the rod piezos - I thought that may be my answer but I'm starting to leant toward a standard pickup as my default for future builds. Cheers.
I see the tail piece in the pics but I don't see the bridge?
Looking at the bottle cap inside the git, If you glued the piezo down inside the bottle cap and then filled it with glue, and then glued the thick layer of glue side to the box, that might explain the underwhelming volume. try the other side, so there is less hot glue between the disk and the wood.
For comparison, try a piezo just attached with blue painters tape to the inside. Yes you will get some handling noise and feedback if pointed at your amp, but it will give you something to compare the other mounting options to, and its easy to move around to find the best spot.
You're spot on, JL. I'll update this thread.
JL raises a good point, where is the bridge? I originally thought you had a hardtail/ bridge combination,which probably made my comment a bit confusing
Thanks for the support guys.
I had a few hours today - here's where I'm at:
1) Heated up the bottle cap to remove the glue and try to save the round piezo [failure - ceramic cracked].
2) Noticed some static / intermittency on my v/c.
3) Decided to scrap the entire harness. I had too many 'repairs' heat-shrinked in there anyway.
4) Re-wired everything with a new v/c and my last disc piezo. I bought 6 and it took me all of them to get this working.
5) Taped the piezo directly to the lid and she's working. It's a different sound but the gain is comparable to my other CBG with the mini-humbucker.
6) Now a dab of glue to hold the piezo in place.
As cool as the bottle cap method looks, I don't know how other guys are getting decent sound from them with all that glue, unless they're running a pre-amp.
JL - as for the bridge, I had one completed from my first build (walnut / maple and bone) and last night I thought if I lowered it to get my action right at the 12th fret (about 2-3 mm), it may positively affect the sound.
Rooky mistake (aka 'I should know better'), I thought I could run the bridge through the jointer using a few thin bits of wood as push sticks. Bad move. The blade grabbed it and tore half of it apart. I did a test run with my hands and was tempted for a second to run the wood through by hand... positive that would have resulted in some missing digits [shaking head]. Anyway.... the bridge is toast.
The bridge location is pretty much in-line with the volume knob, so that's what I'll be re-making tonight.
As frustrating as the lost time was from yesterday, it's all served to sharpen my skills. Woodwork, I'm in my happy place -- electrical... not so much, but I'm learning - that's the name of the game.
As a side note, I just received an email from CBG that my first build is featured - kinda cool.
Thanks again guys.