ATI Audio MX100 - Manual (Page 5)

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labeled 48V phantom power. Check the microphone specification sheet for 9 to 52V or
12 to 48V ratings (includes almost all electrets type condenser microphones). Those few
RF condenser microphones requiring a full 48VDC for phantom power will need an
external power source (generally available from the microphone manufacturer).
On the XP100 only, 24VDC phantom power is individually selected for each input with a
jumper plug P1, P2, P3 or P4. Moving the jumper plug closest to the P1, P2, P3 or P4
marking selects phantom power for the corresponding XP100 input.
Of course, dynamic microphones don’t care if there is phantom power or how much there
is of it or whether it’s even turned on or not so long as they are properly wired with their
coil across pins 2 and 3 of the XLR connector (shield to pin 1). If they are not wired
correctly they may sound real funny with the phantom power turned on (or not at
all…maybe ever again).
LEVEL CONTROLS
Each of the three inputs is controlled by its' own audio taper potentiometer. These
controls preferably operate in the twelve-to-four o'clock range. If you consistently run the
input fader below the ten o’clock position, you should probably reduce the preamp gain
setting one step with the internal dipswitches to assure maximum headroom and control
resolution. If you have a preferred position for a particular input, you can pop out the
knob cap and reposition its' reference indicator line to the twelve o'clock position. A
selection of colored knob caps is included with the unit to allow you to color code the
inputs.
The Master control adjusts the Line Output as indicated by the LED meter. The Master
gains and output stages add 32 dB of additional gain. The Master control should normally
operate above the two o'clock position to maximize internal headroom and optimize noise
performance.
LINE OUTPUT
The output stage of the mixer, A5, utilizes a unique active balanced output driver IC, the
SSM2142, that can sense whether the connected load is balanced and floating or is
unbalanced due to either side being grounded. A balanced output load will be driven with
equal and antiphase levels on the HI and LO output lines. An unbalanced (one side
grounded) load will cause the driver IC to shut off the signal output to the grounded side
of the load and double the output level applied to the other side, thus maintaining equal
output to either type of load. The output stage will drive loads of 600 ohms and higher.
Nominal output is +4dBm with clipping at +22dBm into balanced loads. Maximum
output at clipping is reduced by 6dB when driving an unbalanced load, since the full
output swing of only one driver is available. A jumper plug, P1 located just behind the
output XLR connector selects either +4dBm line level or -50dBm microphone level
output.