[sdiy] preamps for piezos (slightly OT?)

[jarno.verhoeven at ziggo.nl]

Yes, I saw this in the schematic, maybe mine was an older version. But that schematic is a fine starting point.

------ Origineel bericht------Van: Busby BergsonDatum: zo, 14 feb. 2016 21:08Naar: Olivier Gillet;CC: synth-diy DIY;Onderwerp:Re: [sdiy] preamps for piezos (slightly OT?)
Hi there -
The "Mikrophonie" preamp looks very similar to what I'm building: http://musicthing.co.uk/modular/wp-content/uploads/2014/06/Mikrophonie-2-2-Schematic.pdf
Though I'm not using any sort of input cap (nor does the schematic) - that would potentially serve as something of a high-pass, wouldn't it? 
I am also using a TL084, which does have JFET inputs, correct? 
Perhaps it is a matter of experimenting with other ICs. 




On Sun, Feb 14, 2016 at 2:22 PM, Olivier Gillet <ol.gillet at gmail.com> wrote:
The choice of op-amp matters. Bipolar op-amps have a low input
impedance (a few hundred k) which could have an impact on bass
response. An op-amp with JFET inputs would be a better choice here.

On Sun, Feb 14, 2016 at 7:20 PM, Busby Bergson <busby.bergson at gmail.com> wrote:
> hi synthdiys,
>
> i'm currently experimenting with contact mics. they sound pretty good going
> into a guitar amplifier, directly - but if i want to send them through my
> other circuitry, it seems that they require a specialized preamplifier, to
> compensate for their impedance.
>
> i've been using something along these lines:
> http://music-electronics-forum.com/attachments/4228d1232615609-non-invert.buffer.gif
>
> however, i'm noticing that there is still a significant high-passing -
> compared to the bassier direct-to-guitar-amplifier arrangement.
>
> any thoughts?
>
> -  b.b.
>
>
>
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