20mm Piezo discs available on eBay here - 5 for $10.00 plus $2.00 shipping.
http://www.ebay.com/itm/271286851581
http://stores.ebay.com/coldgoldcontactmicrophones?_trksid=3Dp2047675.l2563
On 2015-02-17, at 1:51 PM, Keith Smith [naturerecordists=
] <> wrote:
>
> Hi, Ben.
> Radio Shack sells piezo buzzers for a couple of bucks that are nice and b=
ig. The Schallers can be had at most music stores for around $15, I think, =
and there are lots of sources on the web, of course.
>
> For much better performance you might consider something like this preamp=
if you don't mind doing some soldering. Piezo's are high impedance which i=
sn't a great match for an input expecting to see a low impedance microphone=
.
>
> I just use what's known in the music business as a DI (for converting hig=
h impedance guitar outputs to match with mic preamps). They're just a trans=
former in a steel box with 2 1/4" TR (I/O)and one XLR output. The downside =
of DI's is that they're usually built for rough stage/road use, are bulletp=
roof and probably heavier than you want. I use a dual one that weighs over =
a Kg. Not nice, but I don't hike far and it works very well. That does make=
that preamp I linked to look rather attractive if you want something light=
.
>
> I'm not sure what the transformer turns ratio is. Hopefully David will po=
p back in here with that. Top transformer brands for this are Sowter in th=
e UK and Jensen in the US & Canada, but you can do OK with less expensive s=
tuff if you stay away from the obvious garbage. If you got the transformers=
on their own, you could make up a stereo pair that would be fairly light =
weight with small connectors to suit your recorder.
>
> Either way, use something in there to get a better impedance match. The a=
udio difference is well worth whatever it costs.
> k
>
>
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