[sdiy] Re: General Mic supply question

[Dave Magnuson]

At 12:28 PM 8/29/03 -0500, Paul Schreiber wrote:
>
>I am looking into this topic right now. Here is what I've found so far:
>
>a) the "general accepted" phantom supply is +48V, fed through 6K8 resistors
>b) I think there is some industry standard (IEC?) for this.
>c) However, I've seen *many* non-48V supplies! Examples:
>
>1) 2 9V batteries in a box (18V)
>2) +15V used with smaller resistors (like 2k2)
>3) CMOS oscillators/charge-pump triplers (maybe +20V or so if running off
+12V, 4000-series CMOS)
>
>I guess what I'm asking is: is the +48V a worse-case thing with 300ft of
snarky Hosa cable? Can I
>use say +24V, lower feed resistors and be happy with powering only 50ft of
cable?
>
>Paul S.
>


Hi Paul,

As far as output voltage... most mics will operate at 30V or higher, but
you lose headroom.  Some mics will operate at much lower voltages (18V, etc)

I'm powering Neumann TL-103's a U-87a, An AKG 414 and some other nice
mics...  These then feed into Avalon, Focusrite Red and Grace equipment
through RME converters. so I'm not going to skimp on the output voltage and
sacrifice the sound quality.  If I were using a lesser mic and signal
chain, I wouldn't worry so much about the headroom.  But since I've got
about a $10,000 path to the computer,  I'm not taking chances :)

Dave


Resonant Frequency:
resfreq at hoohahrecords.com
http://www.hoohahrecords.com/resfreq/index.html
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