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to 52 volts. Pin 1 is shield to ground while pins 2 and 3 carry 48 volts DC. The
term "phantom" is derived from the fact that there is no voltage potential
developed across a dynamic microphone transducer that would interfere with its
operation. However, most portable wireless receivers will not operate with 48PH
turned on. We strongly recommend setting inputs to "dynamic"0 for use with all
wireless systems.
D.
LOW CUT FILTERS
Each input channel of the AlphaMix is equipped with an active low cut (high
pass) filter. These filters are activated via the three way switches located below
the adjacent channel fader knobs. These filters will attenuate all frequencies
below a preset frequency at a rate of 12dB per octave. When set at "20Hz",
frequencies below 20 Hz are effectively rolled off with the mixer operating at full
frequency response. Optional low cut filter settings of 80Hz and 140Hz will roll
off the frequencies below these figures at a rate of 12dB per octave (-3dB level at
80Hz and 140Hz respectively. Low cut filtering is important in location recording
where wind noise can cause pre-amplifier overload. Switching the low cut filter
setting to either the 80Hz or 140Hz cutoff setting can minimize this effect. The
low cut filter switches are located on the front of the AlphaMix.
E.
CHANNEL GAIN
In order to limit noise and increase headroom, the channel fader controls are
located in the feedback path of the channel amplifiers.
continuously variable gain rather than just a decrease in channel output level
when an overload situation occurs. This results in increased headroom and
lower chance of signal clipping (severe distortion). The AlphaMix uses sealed,
conductive plastic Clarostat tm pots for channel faders. In addition the gain of
the first pre-amp is continuously variable over a 40Db range. This gain trim pot is
located on the front panel of the mixer and is retractable so it is out of the way
when not being used.
F.
CHANNEL PANS
The new AlphaMix contains front panel mounted pan pots. These pan pots are
used to route the individual input channel's signal to either the left or right
summing buss. These pots are equipped with center detents allowing the pots to
remain centered when the operator so desires. These pots are also equipped
with a retracting mechanism that allows the pots to be pushed in flush with the
front panel after they have been set to the operators desired setting. This helps
keeps the front panel "clean" and uncluttered and reduces the chance of the
operator accidentally bumping the pan pot setting.
H.
CHANNEL METERING
Each input channel on the PSC AlphaMix is equipped with a basic three LED
meter. This meter indicates pre-fader audio level thus it is active even when the
channel fader is turned down. By making this meter pre-fader, you can preset
channel gain levels before opening up the fader. The three LED's are colored
green, yellow and red. These LEDs are calibrated to represent specific audio
6
This provides
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