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9. Re: Phantom power noise - again!!!

Subject: 9. Re: Phantom power noise - again!!!
From: "Klas Strandberg" klasstrandberg
Date: Thu Mar 22, 2007 2:27 pm ((PDT))
Hmmm, might be a mistake here.

Pin 3 of PRO6 IS connected to a 100 ohms resistor and 22 mfd/50 v
condensor to ground,  just as the usual and as the MKH circuit you
refer to. (But connected to + instead)

I think Sennheiser had that solution, as they could use a 16V
tantalum condensor to "ground" the cold output, in this case pin 2..
As you can see on the diagram, there is only 10 v between the 48v and
the 38v +rail. High voltage tantalum condensors were expensive not
long ago, and connecting the cold output to + instead of to ground,
is from that perspective really smart.

Klas.

At 21:17 2007-03-22, you wrote:
> > Raimund Specht wrote:
> >
> > >Yes, that impedance matching will make sure that the disturbances
> > >entering in the cable will be compensated. However, in this way, the
> > >noise originating from the phantom power will only be present on pin
> > >2.
>
>Dan Dugan wrote:
> > If you're talking about noise from the phantom power source in the
> > recorder, it will be applied equally (depending on the accuracy of
> > the series resistors) to pins 2 and 3, assuming equal impedance
> > (which is why the dummy network on pin 3 of the mic) and will be
> > canceled by the balance of the mic preamp.
>
>Yes, of course. I just tried to explain to Klas that his unbalanced
>microphone output (where pin 3 is not connected to the usual series
>resistor) is not able to tolerate any potential phantom power noise.
>The debate started here:
>http://tech.groups.yahoo.com/group/naturerecordists/message/27021
>
>Raimund
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>

Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email: 
website: www.telinga.com







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