If this is the wrong place- shoot me.
Looking through the electric bass players forums there has been interest in Peizo pickups over the last couple of years - including with solid body instruments. Unfortunatly, bass player spend most of there time playing bass ( which they should) rather than puzzling over the science. The definitive website has yet to be written.
There are very expencive piezo bridges and some people have taken the oposite route. Ripping tweeters apart and gluing a single element under the bridge.
Questions:-
Does it need to be mechanically linked to the string? eg "compressed between the bridge and the body. Could it be stuck "near"?
I know that it is best to use a high inpeadance pre amp, but I read that you must not use a bipolar. Why not? Yamaha basses use a TL062
Looking through the electric bass players forums there has been interest in Peizo pickups over the last couple of years - including with solid body instruments. Unfortunatly, bass player spend most of there time playing bass ( which they should) rather than puzzling over the science. The definitive website has yet to be written.
There are very expencive piezo bridges and some people have taken the oposite route. Ripping tweeters apart and gluing a single element under the bridge.
Questions:-
Does it need to be mechanically linked to the string? eg "compressed between the bridge and the body. Could it be stuck "near"?
I know that it is best to use a high inpeadance pre amp, but I read that you must not use a bipolar. Why not? Yamaha basses use a TL062
It needs to placed somewhere were there will be significant pressure changes, or significant flexing. Generally, the only practical place you'll find these things is under the bridge/saddles.
Piezo elements are a capacitive source, as you said, you must use a high input impedance amplifier, there's no reason why it can't be bipolar just as long as it's high impedance.
The TL062 is fet input, it's not all that great with but two redeeming factors, it's cheap and it draws very little current.
P.S. "Musical Instruments" would be a more appropriate forum, but honestly, you probably wouldn't get any useful response posting there.
Piezo elements are a capacitive source, as you said, you must use a high input impedance amplifier, there's no reason why it can't be bipolar just as long as it's high impedance.
The TL062 is fet input, it's not all that great with but two redeeming factors, it's cheap and it draws very little current.
P.S. "Musical Instruments" would be a more appropriate forum, but honestly, you probably wouldn't get any useful response posting there.
opps! I'd forgotten about musical instriments. But until the moderator moves me.......
I also didn't know about the TL062.
Does it need to be clamped hard or "floated". Hard would be better. Since it transferrs the sustain to the wood better. Also its a bigass 5 string with a shed load of tension. Hard would make it stable.
I also didn't know about the TL062.
Does it need to be clamped hard or "floated". Hard would be better. Since it transferrs the sustain to the wood better. Also its a bigass 5 string with a shed load of tension. Hard would make it stable.
I've moved you. You might find it worthwhile to rephrase your question in terms of piezo tweeters and ask it on the loudspeakers forum, or perhaps the analogue forum.
You want a nice high input impedance at your pre-amplifier >1M, so FET input op-amps are good. TL062 allows operation from a single battery, but TL072 is lower noise.
You want a nice high input impedance at your pre-amplifier >1M, so FET input op-amps are good. TL062 allows operation from a single battery, but TL072 is lower noise.
Have you thought about piezo film? It's reasonably inexpensive, relatively easy to interface, and can be placed in some novel spots.
If you haven't already seen it, there's a therad on TalkBass about using Radioshack sourced piezo elements. Also either in the pickups forum or in Luthiers, Rick Turner has made a number of posts about how he designs for his products and the Dtar stuff as well.
If your bass has a Fender style bridge there are some altenative pickup saddle assemblies available. Otherwise get ETS to machine you up one to match your original and spec it with piezo inserts.
If your bass has a Fender style bridge there are some altenative pickup saddle assemblies available. Otherwise get ETS to machine you up one to match your original and spec it with piezo inserts.
Don't laugh too hard..but.. 
A friend and I got bored one day,and grabbed some planks of wood and whatnot,and built up some very crude guitars.
For pickups I used piezo discs on each string (only 4) with a spring(!) soldered to each disc,and then the string (bailing wire) coming off of that,with an adjustable clamp at the top of each string for "tuning".
Added a switch with a cap,for "tone" and a pot for volume,and plugged it into the "phono" input of a stereo reciever..
Worked pretty well,and sounded alot like the bass guitars I've heard in Tool,Primus,etc. I built up a couple quick-n-simple fuzz effects on a breadboard,and we had lots of fun playing along to music..(or,erm,trying to..we suck.)
I still have one of them somewhere..I should take a pic.. LOL
A friend and I got bored one day,and grabbed some planks of wood and whatnot,and built up some very crude guitars.
For pickups I used piezo discs on each string (only 4) with a spring(!) soldered to each disc,and then the string (bailing wire) coming off of that,with an adjustable clamp at the top of each string for "tuning".
Added a switch with a cap,for "tone" and a pot for volume,and plugged it into the "phono" input of a stereo reciever..
Worked pretty well,and sounded alot like the bass guitars I've heard in Tool,Primus,etc. I built up a couple quick-n-simple fuzz effects on a breadboard,and we had lots of fun playing along to music..(or,erm,trying to..we suck.)
I still have one of them somewhere..I should take a pic.. LOL
"If you haven't already seen it, there's a thread on TalkBass about using Radioshack sourced piezo elements"
I already advertise for talkbass too much so it didn't feel right for me to mention it. But now that it's been brought up...
http://www.talkbass.com/forum/showthread.php?t=131882&highlight=Piezo
It includes several posts by a much more poorly informed 🙂smash: ), two years younger me.
I already advertise for talkbass too much so it didn't feel right for me to mention it. But now that it's been brought up...
http://www.talkbass.com/forum/showthread.php?t=131882&highlight=Piezo
It includes several posts by a much more poorly informed 🙂smash: ), two years younger me.
Actually, it was Talkbass that got me started.
What I was really looking for was particulars. "mounted under the bridge" is open to a little interpretation hard or soft?, and the high impeadance preamp is kinda skipped over. (I do have the Yamaha TRB5P scheamatic though). Talkbass reflects what people did as bassists rathed than scientists.
I was just hoping for an alternative slant on the subject from the guys who crunch preamps for breakfast. Ther might be a "better" Piezo 🙂
What I was really looking for was particulars. "mounted under the bridge" is open to a little interpretation hard or soft?, and the high impeadance preamp is kinda skipped over. (I do have the Yamaha TRB5P scheamatic though). Talkbass reflects what people did as bassists rathed than scientists.
I was just hoping for an alternative slant on the subject from the guys who crunch preamps for breakfast. Ther might be a "better" Piezo 🙂
Can you send the Yamaha schematic to me? I'm building a 6 string fretless semi-acoustic, and I will be using piezo and magnetic PU's.
I know, I know, it's not exactly rocket science but I am still eager to see how Yamaha did it.
I'm not sure if the PM button works so here's my e-mail address: Jarno.Verhoeven@planet.nl
Thanks!
Regards,
Jarno.
I know, I know, it's not exactly rocket science but I am still eager to see how Yamaha did it.
I'm not sure if the PM button works so here's my e-mail address: Jarno.Verhoeven@planet.nl
Thanks!
Regards,
Jarno.
I've never done it myself, but from what I've gathered.
Under the saddles works well. If you put it under the bridge screw it down quite firmly but not super hard, about how tightly you'd screw the bridge down normally.
As for the buffer, any EQ and the sort after it would be the standard circuits. The buffer itself would be a very standard single supply noninverting amplifier with a 1-10Meg ohm bias resistor and a lowish gain (I'd guess between one and four).
http://www.analog.com/library/analogDialogue/archives/35-02/avoiding/index.html
Figure 2. Make Rin=10Meg, Cin is unnecessary.
P.S. This particular circuit is easier to build with a FET input opamp because you don't need to worry as much about balancing the DC source impedance and the resulting bias current errors.
Under the saddles works well. If you put it under the bridge screw it down quite firmly but not super hard, about how tightly you'd screw the bridge down normally.
As for the buffer, any EQ and the sort after it would be the standard circuits. The buffer itself would be a very standard single supply noninverting amplifier with a 1-10Meg ohm bias resistor and a lowish gain (I'd guess between one and four).
http://www.analog.com/library/analogDialogue/archives/35-02/avoiding/index.html
Figure 2. Make Rin=10Meg, Cin is unnecessary.
P.S. This particular circuit is easier to build with a FET input opamp because you don't need to worry as much about balancing the DC source impedance and the resulting bias current errors.
I found this pdf about piezo discs as pickups , and a simple preamp using a TL072.
http://www.floraberlin.de/soundbag/sbdownloads/piezos.pdf
I happened to be looking for a single supply solution for a TL072, and stumbled upon it. Then I saw this thread and thought I'd share it.
http://www.floraberlin.de/soundbag/sbdownloads/piezos.pdf
I happened to be looking for a single supply solution for a TL072, and stumbled upon it. Then I saw this thread and thought I'd share it.
Piezo buffer
I've attached a schematic of a preamp I use with my piezo buzzer based pickup on my guitar.
When I built it, I adjusted values so that when the amplifier goes into clipping, it clips both top and bottom equally, and thus has output centered around "0".
with the 10 k load, you have a low impedance output (compared to a guitar amplifier input).
For my old acoustic nylon string, I placed the buzzer element on the inside of the body, directly underneath the treble side of the strings - epoxied in place about 20 years ago and still working fine!😀
I've attached a schematic of a preamp I use with my piezo buzzer based pickup on my guitar.
When I built it, I adjusted values so that when the amplifier goes into clipping, it clips both top and bottom equally, and thus has output centered around "0".
with the 10 k load, you have a low impedance output (compared to a guitar amplifier input).
For my old acoustic nylon string, I placed the buzzer element on the inside of the body, directly underneath the treble side of the strings - epoxied in place about 20 years ago and still working fine!😀
the reason somebody might have said "don't use bipolars" is beacause your "basic" common emitter preamp has a rather low input impedance. fets and op amps (or even a discrete bipolar diff amp) have very high input impedances.
I know people who have used these with great success on acoustic instruments and using Radio Shack piezo buzzers. The pickup is attached to the instrument with a ring of double-face tape. This creates an air pocket between the body of the instrument and the pick-up, so the piezo will pick up the vibration of the area of the instrument it is placed on, almost perfectly.
If the pickup is placed on the outside of the instrument, it is recommended to place it over an air hole - this will pick up almost the total vibration of the instrument and sound as close to the pure acoustic sound as you are going to get. It should sound like the instrument minus the room acoustics, so it is good for recording in a home studio or in live situations.
If installed permanently, you should try multiple locations. The musician I knew (Brad Fish now in Israel) had one installed in the back center on his guitar, but I think he added an extra one under the neck on the inside near the sound hole. He also later had extra ones he would stick in different places to get a different tone. Before he had the 1/4" jack installed permanently, he had the wires carefully taped coming out of the sound hole so they wouldn't hit the strings. These also work well on hand drums. Things like a piano are probably too large, but they make special piezos for that.
After experimenting with different pro solutions for acoustic guitar pickups, these were definitely superior and cheaper.
I wish I could tell you which buzzers to buy, but from what I remember they bought one of each that radio shack carries and tried them all because the stated specs were not accurate. I never heard of using tweeters, but I bet they work similarly.
I good preamp is recommended I believe they put out a slightly lower signal.
If the pickup is placed on the outside of the instrument, it is recommended to place it over an air hole - this will pick up almost the total vibration of the instrument and sound as close to the pure acoustic sound as you are going to get. It should sound like the instrument minus the room acoustics, so it is good for recording in a home studio or in live situations.
If installed permanently, you should try multiple locations. The musician I knew (Brad Fish now in Israel) had one installed in the back center on his guitar, but I think he added an extra one under the neck on the inside near the sound hole. He also later had extra ones he would stick in different places to get a different tone. Before he had the 1/4" jack installed permanently, he had the wires carefully taped coming out of the sound hole so they wouldn't hit the strings. These also work well on hand drums. Things like a piano are probably too large, but they make special piezos for that.
After experimenting with different pro solutions for acoustic guitar pickups, these were definitely superior and cheaper.
I wish I could tell you which buzzers to buy, but from what I remember they bought one of each that radio shack carries and tried them all because the stated specs were not accurate. I never heard of using tweeters, but I bet they work similarly.
I good preamp is recommended I believe they put out a slightly lower signal.
the ones with 3 wires are the smaller ones. wire the red and blue in parallel. the blue wire is a feedback electrode for making self oscillating beepers, and takes up about 1/3 of the transducer surface, and the red electrode the other 2/3. if you separate the element from the plastic case, be careful not to break the element.
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