Boss Audio Systems BR-900CD - Manual (Page 191)

191
Section 8
Using Condenser Microphones (Phantom Power)
Most condenser microphones need a supply of power known
as phantom power in order to operate.
Accordingly, the BR-900CD can supply phantom power at
+48 V to condenser microphones connected to any of the
XLR-type connectors for MIC 1 and MIC 2.
1. Before proceeding, turn INPUT SENS GUITAR/BASS/
MIC2 and MIC knobs fully counter-clockwise in order
to reduce the input volumes, and then move the
MASTER fader and INPUT LEVEL knobs all the way
down.
If any of these volumes is not reduced, a loud click may
be output when the phantom power is turned on or off.
2. Press [UTILITY].
The Utility screen will appear.
3. Press CURSOR [ ] [ ] to move the cursor to “SYS,”
and press [ENTER].
4. Press CURSOR [ ] [ ] to select “Phantom SW,” and
turn the TIME/VALUE dial to turn the setting “ON.”
fig.05-504d
ON: Phantom power will be supplied.
Note that when turned on, phantom power
will be supplied to all XLR connectors for MIC
1 and 2.
OFF: Phantom power will not be supplied.
5. Slowly raise the INPUT SENS knobs, the MASTER
fader and INPUT LEVEL knobs, and confirm that an
audio signal is being received from the condenser
microphone(s).
6. To turn off the phantom power, repeat Steps 1 through
3, and then set “Phantom SW” to “OFF” in Step 4.
• Phantom power cannot be turned on or off individually
for MIC 1 and 2.
• Phantom power is not supplied to the 1/4” phone jack
for MIC 1 or to the GUITAR/BASS jack.
• The phantom power setting reverts to “OFF” whenever
the BR-900CD is turned on. Remember, therefore, to turn
on this power supply whenever it is needed.
• No supply of phantom power will be needed from the
BR-900CD when using an external microphone pre-amp
or a dedicated, external phantom power supply. Ensure
that phantom power is set to “OFF” in all such cases.
Phantom power
Condenser microphones generally contain a pair of thin
opposing electrodes. When a voltage is applied across
these electrodes, any vibration resulting from incoming
audio will be output as electrical waves. However, since
these waves are very weak, they must be boosted using
amplification circuitry within the microphone itself.
Phantom power is used to drive this amplification
circuitry.
Certain types of condenser microphone use internal
batteries as a source of power; accordingly, there will be
no need to supply phantom power in such a case.
Notes when using the Phantom power
• Phantom power should always be turned off when
audio sources other than condenser microphones are
being connected to the BR-900CD’s. In fact, dynamic
microphones, audio players, and the like can be
damaged by this power supply. Always refer to the
user’s manual for the microphone to be used in
order to confirm its phantom-power specifications.
• A supply of phantom power is not needed for
certain types of condenser microphone (i.e.,
microphones featuring internal batteries, electric
condenser microphones, etc.). Ensure that phantom
power is set to “OFF” whenever one of these
microphones is connected.
• The BR-900CD’s MASTER fader, INPUT SENS
GUITAR/BASS/MIC2 and MIC knobs, and INPUT
LEVEL knobs must be moved all the way down
when phantom power is being turned on or off. If
this precaution is not observed, there is a possibility
that amplifiers, speakers, and the like may be
damaged by loud noises generated upon switching.