[sdiy] preamps for piezos (slightly OT?)

[Busby Bergson]

a second pre-amp stage might recover some of the lost bass frequency?

On Sun, Feb 14, 2016 at 4:47 PM, jarno.verhoeven at ziggo.nl <
jarno.verhoeven at ziggo.nl> wrote:

> 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 Bergson
> *Datum: *zo, 14 feb. 2016 21:08
> *Naar: *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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>> >
>>
>
>
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