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Re: MiniDisc Mic Cable Noise

Subject: Re: MiniDisc Mic Cable Noise
From: "Adam Liberman" <>
Date: Thu, 17 Apr 2003 20:50:43 -0000
I believe they remove the plug-in-power resistors feeding the mic
input internally, so it is a different approach with the same result.

This is something we can also do in our shop but it is going to cost
more to do it this way. Although removing the power internally is
the most ideal solution, I don't know that there will be any
practical difference in the result, and adding the cap is much
cheaper and something you can do yourself if you can solder. One
might argue that putting another electrolytic cap in the signal path
is not a good thing, but typically there are already a number of
them inside the machine to begin with.

But you bring up a good point -- maybe in conjunction with the mic
preamp testing I mentioned in my other post, it would be interesting
to see if the internal mod has any effect on mic preamp noise level.

Thanks,
Adam

--- In  "Charles Deenen (home)"
<> wrote:
>
>
> Is this similar to what Sonic Sense does to the dat-mods ?
>
> -cd
>
>
>
> > From: "Adam Liberman" <>
> > Reply-To: 
> > Date: Thu, 17 Apr 2003 20:26:20 -0000
> > To: 
> > Subject: [Nature Recordists] MiniDisc Mic Cable Noise
> >
> >
> > Not quite mic preamp noise, but another source of noise has come
to
> > my attention recently due to a client compaining about noisy mic
> > cables:
> >
> > The "plug-in power" available on the mic jacks of many small
> > MiniDisc recorders can cause bad crackling noises at the mic
cable
> > jack. This is due to small changes in resistance causing a shift
in
> > the DC voltage drop, and can be especially problematic when using
> > the new right-angle mini-plug connectors as they can tend to
rotate
> > a little if not tied down.
> >
> > This can be solved by inserting a small electrolytic capacitor in
> > the XLR cable shell, with the negative lead soldered to pin 2 and
> > the positive lead connected to the wire that was previously on
pin 2.
> >
> > A Panasonic FC series (low ESR, good for audio) cap that works
well
> > and fits in a Neutrik shell is available from Digikey, item #
P11214-
> > ND. It is 27uF/25v, and measured with a Sharp MD-DR7-A MiniDisc
> > recorder introduces only a 0.3dB drop at 20 Hz and no measurable
> > distortion. Caution: Don't use this cap with an outboard 48volt
> > power supply that does not block the 48v volts from the output
side.
> > 48v self powered mics are no problem.
> >
> > Thanks,
> > - Adam Liberman
> > Liberman Sound
> > www.libermansound.com
> >
> >
> >
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>
>
>
> [Non-text portions of this message have been removed]



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