k 2496
Agree! That subject was on this list for a number of months ago.
Note that unless you are going to run microphones with output transformers,=
you don't need to use matched 1% resistors.
Klas.
At 16:12 2005-11-24, you wrote:
>i keep forgetting to post this. one of the simplest
>ways to build a phantom power is to wire a number of
>nine volt batteries together 5 of them will do. it is
>larger than doing it with two nine volt batteries, but
>it is a great deal more efficient so you actually save
>money buying batteries, and it is probably the
>quietest thing you can do. two 1 per cent metal film
>resistors of about 6.8 k, to 100 mfd 50 volt
>capacitors and two 1 mfd film capacitors in parallel
>is all it takes.
>
>umashankar
>
>--- Klas Strandberg <> wrote:
>
> > Just add: I have been working with electronics since
> > 1982. I have learned
> > that it is really difficult to weight together
> > different peoples
> > experiences of some device.
> > This is not only a problem caused by everyone's
> > subjectivity, but also a
> > technical. Just remember that standard components,
> > capacitors and
> > resistors, might have a +/- 20% tolerance. Suppose a
> > condensor (whatever)
> > of one power supply is -20 % and another +20%? Will
> > they both work at -20
> > centigrade??
> >
> > We naturesound people run constantly into problems
> > which no one else
> > bothers much about. We often work "on the limit" of
> > what a product is meant
> > for.
> >
> > Klas.
> >
> >
> >
> >
> > At 12:22 2005-11-24, you wrote:
> > >Yes, you are right in a way - Sennheiser made their
> > own power supplies etc.
> > >To make a good power supply is difficult.
> > >But with new IC's, it is easy to make a lot of
> > shortcuts. Then you can also
> > >make a cheap power supply, with uncertain
> > reliability.
> > >However, my old Tascam DA-P1 has such a simplified
> > power supply and it has
> > >never caused any problems...?
> > >
> > >Klas.
> > >
> > >
> > >
> > >At 04:47 2005-11-23, you wrote:
> > > > >According to my friend it is more or less by
> > chance all the time if a
> > > power
> > > >
> > > > >device works or not. He says that all modern
> > IC-circuit for the purpose
> > > > >have a tendency to drift away in frequency. In
> > his experience only one of
> > > > >them work under all circumstances, stable and
> > pure. In his opinion, the
> > > > >Rolls is a very conventional and thereby
> > unreliable device. ... if it
> > > > >works, it works... kind of.
> > > >
> > > > >Klas.
> > > >
> > > > >Does the phantom power supply he's designed
> > produce less noise? Are
> > > > >you free to tell us more? Is it portable? What
> > operating voltage?
> > > >
> > > > >Rob D.
> > > >
> > > >
> > > >Hi Klas,
> > > >
> > > >
> > > >
> > > >Isn't what you are getting at is that the Rolls
> > might accidentally coincide
> > > >with the correct powering voltages on some
> > microphones?
> > > >
> > > >
> > > >That to be certain that you are providing the
> > correct voltages the
> > > >manufacturer would be wise to supply the mic with
> > the correct phantom power
> > > >unit, just as Neumann has always done?
> > > >
> > > >
> > > >By saying if the Rolls works, it works by chance?
> > and should not be
> > > >considered unless there is evidence providing
> > it's powering that microphone
> > > >model accurately?
> > > >
> > > >
> > > >
> > > >
> > > >Best,
> > > >
> > > >
> > > >Mark
> > > >
> > > >
> > > >[Non-text portions of this message have been
> > removed]
> > > >
> > > >
> > > >
> > > >
> > > >"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:
> > >
> > >
> > >
> > >
> > >
> > >"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:
> >
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
> >
> >
> > "Microphones are not ears,
> > Loudspeakers are not birds,
> > A listening room is not nature."
> > Klas Strandberg
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>__________________________________
>Yahoo! Mail - PC Magazine Editors' Choice 2005
>http://mail.yahoo.com
>
>
>
>"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:
=20
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