Hi Klas,
The differences might also be caused by the design of the microphones.
A fully balanced microphone circuit should work properly even if the
supplied phantom power is not very clean. The balanced input of the
recorder would reject those common-mode noise components.
Regards,
Raimund
--- In 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.
>
>
> 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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