Piezo Pickup Experiment - Page 2 - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 22nd August 2011, 09:25 PM   #12
diyAudio Member
 
Join Date: Aug 2011
Location: Columbus, Oh
Thanks for the literature. I don't think I want my preamp to require phantom power, lol. That is a little "over the top" for me. I did learn quite a bit though.

I am gonna order a J201 and once everything arrives, I'll be set and ready to go.
  Reply With Quote
Old 23rd August 2011, 10:47 AM   #13
diyAudio Member
 
Join Date: Aug 2011
Location: Columbus, Oh
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.
  Reply With Quote
Old 23rd August 2011, 01:14 PM   #14
TheGimp is offline TheGimp  United States
diyAudio Member
 
TheGimp's Avatar
 
Join Date: Aug 2009
Location: Johnson City, TN
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.
  Reply With Quote
Old 23rd August 2011, 01:41 PM   #15
diyAudio Member
 
Join Date: Aug 2011
Location: Columbus, Oh
Quote:
Originally Posted by TheGimp View Post
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 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.
  Reply With Quote
Old 23rd August 2011, 02:49 PM   #16
TheGimp is offline TheGimp  United States
diyAudio Member
 
TheGimp's Avatar
 
Join Date: Aug 2009
Location: Johnson City, TN
Good data here:

http://www.media.mit.edu/resenv/clas...SI-techman.pdf
  Reply With Quote
Old 23rd August 2011, 03:18 PM   #17
diyAudio Member
 
Join Date: Jul 2005
Location: North Derbyshire
Quote:
Originally Posted by wazupwiop View Post
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.
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.
__________________
Nigel Goodwin
  Reply With Quote
Old 23rd August 2011, 04:06 PM   #18
diyAudio Member
 
Join Date: Aug 2011
Location: Columbus, Oh
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/do...Inbox&inline=1

Keep in mind that this is a dual-piezo design and I will be altering it slightly.
  Reply With Quote
Old 23rd August 2011, 08:16 PM   #19
diyAudio Member
 
Join Date: Jul 2005
Location: North Derbyshire
Quote:
Originally Posted by wazupwiop View Post
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/do...Inbox&inline=1
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.
__________________
Nigel Goodwin
  Reply With Quote
Old 23rd August 2011, 08:20 PM   #20
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
 
Join Date: Nov 2005
Quote:
Originally Posted by Nigel Goodwin View Post
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.
and what would be the result of lower impendance load ?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Piezo pickup question snowdog2 Instruments and Amps 7 4th April 2012 11:23 AM
Hexaphonic guitar pickup experiment MisterStarshine Instruments and Amps 16 25th February 2012 01:14 AM
60hz hum,accoustic guitar,piezo pickup,duet>logic pro utterdisaster Instruments and Amps 3 3rd April 2010 10:14 PM
Piezo pickups and onboard preamp for Piezo Gene_Johnson Instruments and Amps 2 19th February 2010 12:55 PM
Piezo pickups and onboard preamp for Piezo Gene_Johnson Everything Else 0 15th February 2010 02:47 AM


New To Site? Need Help?

All times are GMT. The time now is 11:41 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2