Sound Performance Lab 9523 - Manual (Page 7)

7
-35 dB
48 V
Phantom Power
4
PPM Meter
5
2. The phase inversion feature is also very useful when the pola-
rity of the XLR input jack has to be inverted to match the polarity
of the microphone or the microphone cable. The pin assigment of
the XLR connector is as follows: Pin 2 = hot (+) and Pin 3 = cold (-).
3. Sometimes it is desirable to swop the polarity of a micro-
phone because of the sound.
The M IKE M AN can also be used as a gain-on amplifier for line
signals. The input sensitivity of the preamplifier stage is reduced
by 35 dB by pressing the -35 dB switch. The corrected preamplifi-
cation value on the M
IC G AIN control can be ascertained by subtrac-
ting 35 dB from the value set on the potentiometer.
Condensor microphones require a supply voltage of 48 V DC
which supplies the microphone via the balanced audio lines (pins
2 and 3). When the supply voltage is switched on, a phantom
circuit is formed whereby the 48 V DC supply voltage is applied
simultaneously to the two supply lines (+/-) of the microphone
and fed back via the cable screen.
There is no DC voltage between the two modulation lines which
is why dynamic microphones can be used when the phantom
voltage is switched on, without this doing the microphones any
harm.
The influences of noise voltages which can superpose the DC
supply voltage such as hum loops and parasitic currents in the
cable screen are reduced by the phantom power supply.
Moreover, this type of connection is particularly resistant towards
RF.
As there is no potential difference between the +/- supply lines,
the connection technique of the phantom supply is compatible
with moving coil and ribbon microphones.
All microphones with balanced floating output, i.e. also micro-
phones equipped with tubes can be used when the phantom
voltage is switched on.
WARNING: It is essential to switch the phantom supply off if
other types of microphones are used. A line signal source or
an unbalanced microphone may only be used if the phantom
supply is switched off.
The output peak levels (PPM values) are indicated on the LED
display in steps of 3 dB from -18 dB to + 9 dB.
3
Phantom power
according to
DIN 45 596 / IEC 268-15