At 8:21 PM +0100 3/21/07, Klas Strandberg wrote:
>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.
But we don't want people to think there aren't
promising options for quiet, reliable phantom
powering.
So far with mkh30, 40, 80, mbho 603's, AT3032's
and NT1A's, both my Rolls PB224 and my Art
Phantom II portable phantom power supplies have
not produced performance variations I could
detect through long hours under -10 degree to 90
degrees in high humidity. I run the units only on
12 volts, not the 9 volt batteries -- a possible
factor. I keep the units out of the elements but
give them no other special precautions. Rob D.
>
>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
> =A0=A0=A0=A0=A0=A0=A0
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
--
Rob Danielson
Peck School of the Arts
University of Wisconsin-Milwaukee
http://www.uwm.edu/~type/audio-art-tech-gallery/
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