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2. Re: Best way to build simply DIY stereo mics.

Subject: 2. Re: Best way to build simply DIY stereo mics.
From: "Bj=F6rn Eriksson" bempa
Date: Sun May 6, 2012 4:38 am ((PDT))
This is a interesting thread as it raises a lot of good perspectives of the
signal chain between mic capsule to the capturing device.

I am by no means any expert on the impedance matters of matching outputs to
inputs, but so far I know that all the chain counts onto the overall
receivment of the "signal" - the original sound you want to capture. There
is some people twisting their signal cables and a lot of stuff arond the
cable treatments. I am not sure that is something worth spending too much
time into researching but what I am sure counts is the mathing of the
output impedance of mike onto the input impedance of the mic preamplifier.
I think a thumb rule is factor 1 to 10. (?), meaning that if a mike has
output impedance of 400 Ohms the receiving input should have at least input
impedance of 4 kOhms. Impedance is the behaviour of combined capacitive,
resistive and inductive reactance of signals with frequency (as in
audiosignal for an example) compared to the "only" resistive reactance you
have when there is not an alternating signal. (DC). Microphones as mike
preamps has different impedance behaviours and  this seems to be the very
complicated things to get these things right, especially if the mike preamp
has to receive alot of different types of microphones types.

There is alot of information on these matters on the net, and maybe this is
something you already looked upon in your design. Just wanted to raise this
perspective.


All the best,
Bj=F6rn Eriksson

P.S I am also pretty sure this matter have been discussed here now and
then, so sorry if I am bringing up something in reprise.





On Sun, May 6, 2012 at 12:32 PM, Peter Shute <> wrote:

> **
>
>
> Definitely don't apply the solder to the iron, you should apply it to the
> parts being soldered. A tiny bit on the iron helps transfer the heat fast=
er
> and get the parts hot enough to melt the solder. I did it the wrong way f=
or
> decades and never understood why it was so hard.
>
> Do you have a flux pen? Smearing that on the parts first really helps a
> lot.
>
> There are lots of soldering instruction videos on Youtube, so you can see
> how it's done.
>
> Peter Shute
>
>
> --------------------------
> Sent using BlackBerry
>
> ________________________________
> From: 
> To: 
> Sent: Sun May 06 14:42:32 2012
> Subject: Re: [Nature Recordists] Best way to build simply DIY stereo mics=
.
>
>
>
> It does seem simple, so much so that I wonder if I am doing something
> wrong. I have a solder gun, and solder...I clamp the mic wires to the pos
> and neg leads on the RCA plug, melt a small ball of solder on the tip of
> the iron, touch it to the wire/plug lead and let it cool(all takes just a
> second or two). Yet...the mics still sound much noisier then if I just
> twist the wires(off the mic capsules), around the pos/neg leads of the pl=
ug
> and try them that way. The only difference is the solder, so I don't know
> what I'm doing wrong!
>
> ________________________________
> From: Avocet <<brini%40dsl.pipex.com>>
> To: <mailto:
> naturerecordists%40yahoogroups.com>
> Sent: Saturday, May 5, 2012 8:34 AM
> Subject: Re: [Nature Recordists] Best way to build simply DIY stereo mics=
.
>
> > if I can avoid solder altogether, given I've NEVER soldered anything
> > before(and which may be my issue with my other mics) I will.
>
> Paul,
>
> I can only encourage you and anyone else who works with wires to get
> the hang of soldering. It really is quite simple and gives you the
> freedom to make up leads and adaptors as you want them. It remains the
> only secure way of making a connection.
>
> When I was working I used to cut the ends off all my mic cables about
> once a year and resolder them. Only once did I have a lead go down on
> me and that one came from our tech stores.
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
> ------------------------------------
>
> "While a picture is worth a thousand words, a
> sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>









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