The problem, Rob, is that a those modern phantom power devices may
work fine under certain circumstances, with certain microphones and
certain loads / temperatures e.t.c. - while they get unstable under
other circumstances.
There is at least one IC which is 100% stable under all conditions,
but then it is a little more expensive than the other ones + you need
a coil, which takes space in the machine.
Klas.
At 19:01 2007-03-21, you wrote:
>At 6:07 AM -0700 3/21/07, umashankar wrote:
>
> >
> >i think the culprit in all these is the switched mode phantom power
> >and probably the best thing would be an outboarded phantom power. it
> >does not always have to be 48 volts - depends on the mike of course,
> >but i have run oktava mko12 (a simple resistor for the condensor DC
> >voltge) on 18 volts with only a small loss in sensitivity.
> >
> >umashankar
>
>This possibility goes way back in our discussions. I bought the parts
>to make up one that supplied 48 volts via multiple batteries with
>Klas' help on the schematic. A few weeks later, Eric Benjamin tested
>my Rolls PB224 portable phantom power supply and reported that the
>noise level was probably insignificant even with the best gear. This
>was also consistent with my test comparing the NT1-A->744 (phantom)
>vs NT1-A-> Rolls PB224 ->744 (non phantom). As the Rolls is only
>$70USD, the need for a battery-only unit became lower, but no A/B
>test has been done to the best of my knowledge.
>
>If any one has a battery-only-powered phantom supply they could send
>me for a few days, I'll run an A/B test. The NT1-A's will run fine on
>30 volts. Rob D.
>
>
>--
>Rob Danielson
>Peck School of the Arts
>University of Wisconsin-Milwaukee
>http://www.uwm.edu/~type/audio-art-tech-gallery/
>
>
>
>"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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