> Officially Phantom power is 48 volts DC, but in the past a number of low=
er priced mixing desks didn't bother to incorporate a power supply providi=
ng a 48 volt tap in addition to the + & - 12 to 18 volt rails needed for t=
he circuitry. They started supplying Phantom voltages in the range of 24 t=
o 36 volts, which many condenser mics are happy with. Neumann mics specifi=
cally (I know from personal experience) will not operate at less than 48 v=
olts without seriously compromised dynamic headroom, but the makers of the=
less than fully pro desks gambled that their end users would likely not a=
lso be using high end microphones. Today it's quite rare to find less than=
48 volts available on any mic preamp. Generally speaking most mics will e=
xhibit higher self noise & reduced dynamic range when powered by less than=
48 volts.
Officially there are three species of Phantom power: 12V, 24V and 48V. Merc=
ifully, the industry has ignored the 24V standard.
48V has become the standard for professional work. 12V was for a long time =
the standard for sound reinforcement equipment; they could use the 15V or 1=
8V power supply rail in the mixer, very simple. Lots of phantom powered mic=
s are fine down to 12V for that reason, but it's definitely a know-your-gea=
r situation--knowing what a particular mic needs, and knowing what a partic=
ular mixer supplies.
-Dan Dugan
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