Tuesday, 29 April 2014

Acoustic Piezo Preamp

Request for a simple opamp piezo preamp based on this circuit:
http://www.eleccircuit.com/acoustic-guitar-pickup-circuit-using-tl071




38 comments:

  1. Sweet! I have needed something like this for so long. I put a Piezo bridge pick-up in my 335 imitation which needs to be tamed. I am guessing the 100n in the input will be for the tone?

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  2. I've been looking for an acoustic preamp for a while. Thanks! Is the LED just an indicator?

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    1. Looks like power indicator to me

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    2. Yes the LED is for an Led positive side and then the negative side goes to your foot switch or to ground if not using a foot switch with this. Looks like the 1k resistor is for led brightness too. so that may need changed depending on what color led you use. If using a bright blue 30-33k is great on those otherwise they blind ya. On the UV ones sometime I run a 1-2k on those. They are not that bright.

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    3. Yeah, I was thinking that's pretty low for a CLR, I have a blue that I used a 3k3 and it will blind you! That's one reason I was asking if it was only an indicator.

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    4. 1K was used because that was in the schematic, I tend to use 2K2 to 4K7 most of the time.

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  3. This may be the answer for the U-Bass I built a while back. I used a bridge piezo but am lacking over all signal and need to kill the highs. This and a cap change on the tone pot may cure it.

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  4. This would be great for my Cigar Box Guitar.

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    1. That was my first thought upon seeing this layout!

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  5. is it basically a buffer with a volume control?

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    1. No it's not a buffer it's a preamp gain stage. The gain isn't huge, 1+(220/100) and so 3.2x but gain all the same.

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  6. Any reason you couldn't go right out of this board into a Sea Blue in the same box, and end up with a preamp with low/mid/hi controls? I guess I'd take full volume from here into the Sea Blue and use the Volume pot on the Sea Blue as the output volume control.

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    1. I was thinking the same thing, that or the Anderton Super Tone control.

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  7. Could i use a TL072 instead of the TL071? :)

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    1. You could, but not with this layout. This is setup for a single opamp and so you could use something like a LM741, LF351 or similar.

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  8. I believe you can tag this as verified. Built this morning for fun.... it makes my acoustic guitar loud. So, I guess it's doing it's job. No weird sounds or humming, and the Vol pot works as expected. Thanks for another great layout!

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    1. If I wanted to take this at full volume into an EQ board in the same box, I would just bring Vol 1 to the EQ and forget about Vol 3, right?

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    2. Excellent, thanks for verifying. No, take the volume 3 wire to the EQ and forget about the volume 1 and 2 wires

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  9. I've been looking for a way to make a homemade preamp for my double bass for a long time. Double bass preamps are expensive and I couldn't justify it for my second instrument.

    I'd like to give this some tonal shaping. Could I hook the output straight into a baxandall tone stack or similar and then out from there?

    Is this preamp suitable super low double bass frequencies as it is, or is it more suited to guitar? Or is it just for anything?

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    1. dave,
      ya may wanna double the values of the input and output caps to drop it down an octave for a double bass. 10u is probably ok for the output. i'd probably try like 220 or even 470n for the input... but the huge mass of the upright strings may overdrive it and make it fuzz. i don't own an upright anymore, gonna try it on my mandolin. ;)

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    2. Dave, did you ever build this for your upright? If so, how'd it turn out and what values did you settle on? My buddy could use one of these...

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  10. Hi,all
    Thanks for like my circuit.
    You can use any IC-op-amp. But different sound.
    I think TL-071 best and LF351, UA741 is Low sound quality cheaper.

    Momename
    http://www.eleccircuit.com

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    1. Thank you for sharing your circuit :o)

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  11. hay iviark cant i request layout woody acoustic simulator or Mooer Audio Acoustikar
    thank before

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  12. hi, if the volume is just the same than the IC is probably the problem, right? I'm using a LM741 since I don't have anything else in stock.

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    1. The gain is 3.2x no matter what IC you use, and it should work perfectly well with an LM741. It isn't a big boost but it should be noticeable

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    2. Thanks for the reply. I was actually trying if it would amplify the bass of my DIY foot drum enough. But this layout might not be the right one than. Up to searching for something else!

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    3. Increase the 220K resistor. That will increase the gain and so may give you the boost you want.

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  13. Would this work with the tonemender eq?

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  14. hi! On the original schematic theres a - and + side of the piezo, but here there's just one hole. How can I solve this? :) thanks for the answering, I'm new here :)

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  15. Does anyone know what the input impedance is on this circuit, and/or how to calculate it?

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  16. I built this for use with a double bass. We have two cheap piezo pickups on the bridge running into the two channel mixer also found on this site. The single output from the mixer is fed into this preamp and then through the sea blue eq also on this site. I combined them all in one box. With volume controls on each input, I bypassed the volume control on the preamp and use the eq volume as a master on the output. I also added the mid control to the eq. No values were changed to adapt for bass and it sounds incredible. No distortion, no hum. This preamp also works great on a squareneck resonator with a goldtone abs condenser clip on mic.

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    1. Does THIS schematic give you enough low end for upright bass?

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  17. Just gonna ask, I'm looking for an electrostatic preamp design for my upright, and can't seem to find anything online. Is it too complex to build one or is it just not used?

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  18. I'm thinking about building this for my electric-upright-bass-hybrid thingy.
    Will this have enough low end?
    I read people use an extra buffer to get the low end.
    My piezo experiences are pretty low. Haha.
    Can you help me out?

    And what will happen when I use 250k or 500k for the volume pot instead? (

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    1. I've built this and should have read the comments first. I've installed 2 piezos into an electric, using a pushpull to swap the middle pickup out for the piezos.

      I'm running this directly (no volume pot) into an LPB1 on vero using the trimmer to adjust the volume for the piezos to be equal to the regular pickups. I saw reading this that increasing the 220k would increase the gain - could that resistor be swapped out for a trimpot?

      There's not a lot (any) bottom end. I tried a klon buffer into the LPB1 originally and it sounded horribly fuzzy in a very bad way.

      Would a different (higher) input impedance help? How would we improve/fix that on this circuit?

      http://www.scotthelmke.com/Mint-box-buffer.html

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