Connections, Controls And Indicators; Operating Instructions; Stereo Operation; Front Panel - Gemini XPM-600 Service Manual

Connections, Controls and Indicators

Rear Panel

Note: 120V and 230V units have different types of output
connectors on the rear panel.
Input Section:
There are two parallel input connectors (one female XLR and one
1/4" jack) per channel. Either can be used as an input or as a link to
chain amplifiers.
XLR Input Jacks (1, 5): electronically balanced inputs accept a standard
XLR male connector. Pin 1 = shield/ground, pin 2 = hot or positive (+)
and pin 3 = cold or negative (-).
1/4" Phone Input Jacks (2, 4): accept a balanced as well as an
unbalanced line level signal. The unbalanced line uses a standard tip-
sleeve connection. The tip is positive and the sleeve is negative/
ground. The balanced line uses a tip-ring-sleeve connection. Tip =
hot or positive (+), ring = cold or negative (-), and sleeve = shield/
ground.
Operation Mode Switch (3): switch is used to set the unit for Stereo
mode, Parallel Mono mode or Mono Bridge mode.
AC Power Section:
Fuse (7): replace fuse with those of proper type and rating.
Ground Lift Switch (8) is used to lift the ground from the chassis. See
the Ground Lift Switch Instructions for more detail.
AC Cord Outlet (6) is used to attach the power cord to the unit.
Output Section:
Disconnect unit from the AC power source before making any
connections. Pay close attention to polarity (shown on the back of the
unit) when connecting your speakers. Connecting your speaker systems
using the wrong polarity will not damage your speakers, but it will impact
the quality of the sound (lack of bass and incorrect stereo image).
Speaker Outputs for 120V Unit (9, 10, 11): the speaker output jacks
are 5-way binding posts that will accept a standard banana plugs,
spade lugs or bare wire. Make sure that all the connections are clean
when using bare wire connections. If any strands of wire from one
connector touch the adjacent connector, the sound will be distorted,
and your amplifier will overheat and go into protection mode.
Speaker Outputs for 230V Unit (9, 10, 11): Neutrik Speakon
connectors are provided to connect speakers to the amplifier quickly
and easily. They are high current rated and provide very stable and
durable contacts. A third Speakon connector in the center is provided
to be used if the amplifier is in the Mono Bridge mode. Every
Speakon connector has pin 1- as negative and pin 1+ as positive.
NOTE: Total speaker impedance must not be lower than 4
Ohm per channel for Stereo and Parallel Mono modes, or 8
Ohm for Mono Bridge mode.

Front Panel

Power Switch (20): turns the unit on and off.
Power LED (19): the power LED lights when the power is on. If the
power LED does not light, refer to the trouble shooting guide.
Mono LED (12): the mono LED will light when you have set the rear
panel Operation Mode Switch (3) for parallel mono operation.
Always make sure that this switch is in the correct position and that
all speaker connections have been made correctly for the mode of
operation you wish to use before powering up the amplifier.
Bridge LED (13): the bridge LED will light when you have set the rear
panel Operation Mode Switch (3) for mono bridge operation. Always
make sure that this switch is in the correct position and that all
speaker connections have been made correctly for the mode of
operation you wish to use before powering up the amplifier.
Signal LED (14): the signal LEDs for each channel show when a signal
is present. In Mono Bridge mode, both the channel A LED and the
channel B LED will light in unison.
Clip LED (15): the amplifier has true clip LEDs to help you properly
control the amplifier's output and achieve undistorted sound. The clip
LEDs for each channel light when your signal level is so strong that
the distortion reaches 1% THD. The clip LED should not remain
constantly on or flash repeatedly during operation. For clean sound
reproduction, the clip should only light occasionally for an instant. If
the LED remains on or flashes repeatedly, you will hear distorted
sound that can be damaging to your speaker systems. If this occurs,
reduce the signal level by lowering the input level control for the
channel that is clipping or reduce the level at the source. If the clip
LED lights when no signal is present, it may indicate a RF signal on
the output which may cause damage to speakers (the RF signal will
not be audible). Please note that when you are using the amplifier in
the Mono Bridge mode, both clip LEDs of the bridged channels will
operate simultaneously.
Protect LED (16): when you first turn on the amplifier, the protect LEDs
light briefly during a turn-on delay which indicates that the outputs are
disconnected internally. There will be an audible click when the
outputs reconnect and the protect LEDs will turn off. Otherwise, the
protect LED indicates that there is a problem either in the amplifier's
external connections, load or temperature conditions or its internal
functions. If one of these situations occur, the amplifier senses the
problem and automatically switches into protection mode. The LED
will light to warn you of the trouble and the amplifier will stop working.
If this occurs, switch off the amplifier and refer to the Trouble
Shooting Guide. If the protect LED remains lit when resuming
amplifier operation, do not use the amplifier and contact an
authorized service technician.
Level Controls (17, 18): establish the input levels required for each
channel. Only the Channel A Level Control (17) works in Mono
Bridge mode.

Operating Instructions

THE AMPLIFIER'S POWER MUST BE TURNED OFF WHEN
CHANGING MODES OF OPERATION.

Stereo Operation

The unit has two channels for stereo operation. Each channel
provides a separate and discrete signal at the speaker outputs according
to the signal received at the inputs. The following instructions are for
applications with 4 Ohm or 8 Ohm speakers of matched power ratings.
1. With the power off, set the OPERATION MODE SWITCH (3) to the
STEREO position. When the power is on, the Mono and Bridge LEDs
on the front panel will not light. If these LEDs illuminate, you have the
switch in the wrong position. Correct before continuing.
2. With the power off, connect your input cables to the channel A and B
inputs using either the XLR INPUT JACKS (1, 5) or 1/4" INPUT
JACKS (2, 4) of each channel. The other channel A and channel B
inputs can be used to link to an additional amplifier.
3. Connect the loudspeakers to the channel A and channel B SPEAKER
OUTPUTS (9, 11). THE TOTAL SPEAKER LOAD MUST BE AT
LEAST 4 OHMS PER CHANNEL. If you try to operate at a lower
impedance, the amplifier will go into protection mode and stop
operation until you correct the load conditions.
4. With the LEVEL CONTROLS (17, 18) of both channels set to zero
(fully counterclockwise), turn the POWER SWITCH (20) on. Apply a
signal to the input of the amplifier. The level of the input signal should
be as high as you will ever need it to be. This way, it will be as high
above the amplifier's noise floor as possible, ensuring an excellent
performance and signal to noise ratio. Adjust the LEVEL CONTROLS
for each channel to achieve the desired maximum listening level.
Note, when the clip LEDs light, there is distortion present in the
amplifier's output section. If a clip LED remains on or flashes
repeatedly, reduce the signal level by lowering the input level control
for the channel that is clipping or reduce the level at the source.
Page 4