[sdiy] help me not electrocute my friend real quick -

[Dave Manley]

With a transformer the only coupling is magnetic, isolating the mic
from any current paths through the amp.  You'd want the transformer
near the amp, at the far end of the cable from the mic.

Without a transformer if the amp accidentally shorts line voltage
onto one of the mic wires you could get shocked.  The suggestion
to plug the amp into a ground-fault interrupter (GFI) protected outlet
is probably adequate - no transformer required.

If the ice is in a plastic jug or bucket on an insulating surface there's
really not much risk anyway.

-Dave

Horton wrote:
> Why hook it up to a transformer?
>
> AH
>
>
>
> On Mon, Jan 26, 2009 at 7:20 PM, HL-SDK Synths <syntroniks at gmail.com> wrote:
>   
>> As long as the amplifier that this is being connected to doesn't fail, there
>> is no real risk. The input is an input, and should accept signal from the
>> piezo, rather than try to hurt anyone. I think you (or your friend) will be
>> pretty satisfied with the results. I can almost guarantee good sounds.
>> Waterproofing is a _VERY_ good idea as well. Now that I think of it, I
>> wouldhook it up to a radioshack transformer.
>>
>> One with 1K to 8 ohm impedance. Something therabouts.
>>
>> On Mon, Jan 26, 2009 at 7:04 PM, Horton <horton.andrew at gmail.com> wrote:
>>     
>>> I'm about to build my friend a contact mic. I found instructions here
>>> - http://brokenpants.com/?page_id=94 - and I have a few spare piezo
>>> elements hanging around, so I figure it's a quick job, no problem.
>>>
>>> However, she specifically wants to freeze this mic in ice and use it
>>> to record the sound of the ice cracking as it melts. I figure I'll
>>> just dip the entire piezo end in plasti-dip, let it dry, and she's
>>> good...waterproof. Will that be fine? I have no idea what she'll be
>>> plugging it into on her end, but whatever it is, it's coming off of
>>> wall power and not batteries.
>>>
>>> AH