Hey all,
Over the next few months, I am going to be experimenting with piezo pickups. I am sure that many of you have toyed around with acoustic guitars and a piezo, but I am going to take it one step farther, with a little bit of applied science.
I don't know if you have ever heard of a man named Peter Sesselman, but he makes guitar pickups from piezos, and he has his craft down to a science.
Piezos are affected by three things: vibration, bending, pushing and pulling. I have talked to Mr. Sesselman and watched some of his youtube videos. He talks about the design and construction of his piezo pickups, and this is what I plan to experiment with.
Vibration is the first stimulus of a piezo. Often times, this will be the main source of sound from a piezo-based pickup. the issue with this is that it is the weakest stimulus out of the three stimuli I mentioned above; however, if you combine the effects of the other two stimuli with the vibration, you can tweak the dynamics of a piezo-based pickup.
To stimulate the pulling and pushing of a piezo, I am going to put a counterweight on one side of the piezo. Peter Sesselman describes this in his videos, along with the rest of the things I will be talking about. The counterweight controls the treble frequencies of the pickup. I am going to try different weights of objects and post the results. I am going to try coins, metal washers, and bolts.
To stimulate a piezo through bending, only the center of the piezo should be mounted by a small dot of adhesive. A cap can be placed along the edge of the piezo to slightly bend the piezo as you play, creating bass frequencies. I am going to take a dowel rod and make a small cap. I am going to test different amounts of wood and etc. It should be interesting.
The piezos I ordered should be here this week. I will hopefully get some testing in, but I have to keep up with my school schedule. I will post results as I go. Stay tuned, this should be pretty intriguing.
Over the next few months, I am going to be experimenting with piezo pickups. I am sure that many of you have toyed around with acoustic guitars and a piezo, but I am going to take it one step farther, with a little bit of applied science.
I don't know if you have ever heard of a man named Peter Sesselman, but he makes guitar pickups from piezos, and he has his craft down to a science.
Piezos are affected by three things: vibration, bending, pushing and pulling. I have talked to Mr. Sesselman and watched some of his youtube videos. He talks about the design and construction of his piezo pickups, and this is what I plan to experiment with.
Vibration is the first stimulus of a piezo. Often times, this will be the main source of sound from a piezo-based pickup. the issue with this is that it is the weakest stimulus out of the three stimuli I mentioned above; however, if you combine the effects of the other two stimuli with the vibration, you can tweak the dynamics of a piezo-based pickup.
To stimulate the pulling and pushing of a piezo, I am going to put a counterweight on one side of the piezo. Peter Sesselman describes this in his videos, along with the rest of the things I will be talking about. The counterweight controls the treble frequencies of the pickup. I am going to try different weights of objects and post the results. I am going to try coins, metal washers, and bolts.
To stimulate a piezo through bending, only the center of the piezo should be mounted by a small dot of adhesive. A cap can be placed along the edge of the piezo to slightly bend the piezo as you play, creating bass frequencies. I am going to take a dowel rod and make a small cap. I am going to test different amounts of wood and etc. It should be interesting.
The piezos I ordered should be here this week. I will hopefully get some testing in, but I have to keep up with my school schedule. I will post results as I go. Stay tuned, this should be pretty intriguing.
With this design of a pickup, a preamp isn't necessary. As I mentioned, the vibration of the piezo is the weakest stimulus out of the three stimuli that affect a piezo. The bending (the strongest force) and pushing force on the piezo really boost the output of the piezo (2-5x).
Think about this. Piezos are used in buzzers. These buzzers utilize the piezo to its full potential. Those little buzzers are REALLY loud. Some can reach up to 100 dB.
By using all three stimuli, I can minimize the need for a preamp. I will have to do some testing, but we will see.
Think about this. Piezos are used in buzzers. These buzzers utilize the piezo to its full potential. Those little buzzers are REALLY loud. Some can reach up to 100 dB.
By using all three stimuli, I can minimize the need for a preamp. I will have to do some testing, but we will see.
No you can't , you MUST use a very high input impedance preamp, guitar amps etc. aren't usually high impedance enough. It's not gain that's the problem, it's the impedance.
But to be honest, just going from what you've said, the entire thing sounds a bit of a scam.
I believe that Mr. Sesselman's work is not a scam. People have reviewed his pickups on multiple with 4 and 5 star reviews. I have researched this on other websites about the bending and pushing effects on piezos. The science is there, but I am going to do some testing. This is just kind of a fun experiment. My guitar already has electronics, I am just messing around for fun and scientific purposes. If it doesn't work, it doesn't work.
If Mr. Sesselman's work is a scam, it is about to be exposed for what it is. I am not biased, this just sounded like fun and I thought I would try it. It will be interesting to see what happens, so stay tuned.
Most modern amps can handle high impedances if memory serves me correctly. In fact, many guitar amps have Hi and Lo inputs to provide an input to suit the needs of modern equiment that operates at high impedances.
That said, older amps (Pre-80's) may have an issue with higher impedances due to design. I am not going to be using a 30 year-old amp to test the piezo pickups. I am going to be using a solid-state Line 6 amp. I have seen people on youtube plug straight in to an amplifier with no issues to speak of. If I actually need a preamp, I have the electronics skills to make one. I don't think I will though.
Your memory doesn't 'serve you right' - you have it the wrong way round, modern amps have the normal medium impedance input, and a low impedance one specifically for active guitars.
Modern equipment doesn't operate at high impedances, it's generally a poor idea.
Check this video out and tell me what you think:
peter rambles on about piezo acoustic guitar pickups and how they work DIY - YouTube
peter rambles on about piezo acoustic guitar pickups and how they work DIY - YouTube
he is certainly trying hard to explain it
well, I think all who are dedicated to solve the problems of amplifying acoustic instruments are serious people
I talked to Peter Sesselman again, and I specifically asked about impedance issues. He sent me a 3-resistor attenuator circuit, and said that it would fix any issues I have with impedance.
I am not going to build the JFET buffer just yet. I am going to build Mr. Sesselman's circuit, and then, if that doesn't work, build the JFET buffer.
Thanks for all the comments on the thread. You guys have been a HUGE help so far.
I am not going to build the JFET buffer just yet. I am going to build Mr. Sesselman's circuit, and then, if that doesn't work, build the JFET buffer.
Thanks for all the comments on the thread. You guys have been a HUGE help so far.
CBGs often times use a Radio Shack 273-064 piezo buzzer as a pickup. The piezo element is removed from teh plastic housing, and the bare piezo element is mounted inside the guitar.
I have not heard of any complaints about drive level, and have tested one such setup with a tube guitar amp (1M input resistor).
The caviat is that there may be guitar amps with much lower Zin than the traditional 1M or 470K. The Gibson Falcon uses 150K for the input resistor to ground. Some SS amps may be lower. If the Zin is too low it will start loading the pickup and change the tone so most amps stay with 1M Zin.
I have not heard of any complaints about drive level, and have tested one such setup with a tube guitar amp (1M input resistor).
The caviat is that there may be guitar amps with much lower Zin than the traditional 1M or 470K. The Gibson Falcon uses 150K for the input resistor to ground. Some SS amps may be lower. If the Zin is too low it will start loading the pickup and change the tone so most amps stay with 1M Zin.
I ordered piezo elements from futurlec.com. I don't have to pry them out of a casing. The attenuator circuit is supposed to help with all of the piezo to amp stuff.
The attenuator basically lowers the impedance by using resistors to take some of the load off the signal. I hope I phrased that correctly, lol. I am newer to this electronics stuff.
Can you post it here?, a three resistor attenuator sounds a bit strange (PI and T attenuators are usually used for impedance matched RF circuits).
What values does it use?.
To be honest a single resistor in series with the PU would give you a high input impedance (no need for two or three). and would minimise the loses.
But any attenuator solution relies on having plenty of extra gain available in the amplifier.
Basically it is a 100k resistor that jumps from hot to ground on the output jack. There is another resistor between 100k and 250k that is linked between the hot output of the piezo and the hot of the jack. Here is a little diagram:
http://us.f1146.mail.yahoo.com/ya/download?mid=1%5f46685%5fADe3iGIAAFCWTlLm%2fgCZ3EhEnc4&pid=2.2&fid=Inbox&inline=1
Keep in mind that this is a dual-piezo design and I will be altering it slightly.
http://us.f1146.mail.yahoo.com/ya/download?mid=1%5f46685%5fADe3iGIAAFCWTlLm%2fgCZ3EhEnc4&pid=2.2&fid=Inbox&inline=1
Keep in mind that this is a dual-piezo design and I will be altering it slightly.
The picture doesn't display.
But sticking a 100K(250K) and 100K as an attenuator is simply presenting a pretty low load impedance across the piezo, worse than it not been there (a guitar amp is probably as high or higher impedance than that).
I would suggest for a piezo you should be looking at loading in the megaohms 2M2, 4M7, perhaps even 10M. Piezo's really need high impedance loading.
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