12v phantom vs 48v phantom
joe origlieri
just a quick question about the difference between 12v phantom power
and 48 volt.
can you power a 48 volt phantom mic with 12v phantom power? i
remember hearing from somewhere that few mics actually use the full 48
volts. is this correct?
not that i want to actually try this with my gear. just curious.
thanks,
joe
Richard Crowley
> just a quick question about the difference between 12v phantom
> power and 48 volt.
Traditionally, "phantom power" implied the full 48V. Some
manufacturers have been thoroughly trounced for claiming
"phantom power" and even using the term "48V" on equipment
that provided only ~30V. (e.g. M-Audio MicroTrack 1)
> can you power a 48 volt phantom mic with 12v phantom
> power?
In many cases, yes. Sometimes with no difference in performance,
and in other cases, with reduced performance (level-handling,
distortion, etc.)
> I remember hearing from somewhere that few mics actually
> use the full 48 volts. is this correct?
>
> not that i want to actually try this with my gear. just curious.
It is a complex question and there is no simple generic answer.
There is equipment (primarily battery-operated devices) which
provide "phantom power", but at something less than the standard
48V. Some as low as 9-12V. But then most (but NOT all) modern
condenser mics can opeate on something less than 48V. Some mics
use the phantom power to charge the condensor element directly.
Those mics will become less sensitive with lower "phantom power"
supply voltages.
Most electret (permanently-charged) condenser mics use the
phantom power only for the amplifier section of the mic, and since
mic levels are very tiny fraction of one volt, 48V (or even 24V or
12V) is rather more than is needed for such tiny signal levels.
However note that some mics (like DPA) even though they are
electret permanently charged, reguire high voltages for other
(secret?) reasons. There is a range of DPA mics, for example
that runs on 130VDC even though they are electret permanently-
charged and use solid-state amplification.
Note however that with many designs, lower supply voltages
will reduce the dynamic range which causes the mics to distort
at lower sound levels. And there are some mics which effectively
refuse to work at anything less than the full 48V power.
Soundhaspriority
"joe origlieri" <jorig...@gmail.com> wrote in message
news:73740a13-07b3-4296...@h23g2000vbc.googlegroups.com...
There is potential confusion here between T-power, which is 12 volts, and
phantom power, which is wired differently. It is important to keep in mind
in a discussion. I've seen a few gadgets that allow phantom to switch
between 48 and 12 volts, but I am unaware of any phantom devices that
exclusively provide 12V. The common cheat, ala M-Audio, is 36V.
Bob Morein
(310) 237-6511
JayRose
polarized mics can use 12V or even lower phantom (the AKG C451/C460
series comes to mind). They boost the DC internally to get the much
higher voltage needed for the capsule. And because their power circuit
is self-regulating, they work exactly as well at low voltages as they
do at 48v.
AKG included the internal schematics with the mics. It's a fairly
simple arrangement. AFAIK, docs are still available on their website.
These mics do draw a few MA more at the lower voltages, but nothing
major. For a while I was using a AKG CK9 true condenser long gun with
an official AKG external XLR phantom supply: it used a transformer, a
standard 9V battery, and a limiting resistor, period.
(Not to be confused with the AKG BlueLine, which are fairly similar
mics but do use an electret element.)
rraudio
without performance issues. Some true condensers need a full 48V.
I agree with Bob Morein, there has been always been confusion on
12V."T" (A-B) power Bias voltage is another discussion..
OT: "Phantom Power" was originally developed and copyrighted by Georg
Neumann GmbH.
Jon Tatooles
were still labeled "simplex" power. Yet another confusing label that is
helpfully gone. Users always got confused between simplex/phantom, T/AB,
and bias.
Jon Tatooles
Sound Devices, LLC