[sdiy] preamps for piezos (slightly OT?)

[Busby Bergson]

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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> >
>
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