Specifications; Using The Signal Ground Lift Switch; Parallel Mono Operation - Gemini GXA-1600 Operation Manual

3. Connect the loudspeakers to the CHANNEL A and CHANNEL B
SPEAKER OUTPUTS (9, 11). THE TOTAL SPEAKER LOAD MUST BE
AT LEAST 2 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
counterclockwise), turn the POWER SWITCH (12) ON. With the level
controls of your MIXER or other INPUT device turned all the way DOWN,
turn the amplifier level controls all the way up for desired loudness from
your speakers. Note, when the CLIP LED (17) light, there is distortion
present in the amplifier's output section. If a CLIP LED (17) 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.
5. Now adjust your MIXER or other INPUT source to your desired listening
level. You also have the choice of keeping the volume of both speakers
equal, or for certain situations you can adjust the volume so one side will
be louder than the other.

PARALLEL MONO OPERATION:

Follow these instructions for PARALLEL MONO operation using a single
input cable, and you will have the same monophonic signal on both the
CHANNEL A and the CHANNEL B outputs. Each channel's output is
controlled independently by that channel's level control.
1. With the power off, set the OPERATION MODE SWITCH (8) to the
PARALLEL MONO position. When the power is on, the MONO LED (14)
on the front panel will light. If the LED does not 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 input
only using the either the XLR INPUT JACK (5) or 1/4" INPUT JACK (7) of
CHANNEL A. The other CHANNEL A input 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 2 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
counterclockwise), turn the POWER SWITCH (12) ON. With the level
controls of your MIXER or other INPUT device turned all the way DOWN,
turn the amplifier level controls all the way up for desired loudness from
your speakers. Note, when the CLIP LED (17) light, there is distortion
present in the amplifier's output section. If a CLIP LED (17) 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.
5. Now adjust your MIXER or other INPUT source to your desired listening
level. You also have the choice of keeping the volume of both speakers
equal, or for certain situations you can adjust the volume so one side will
be louder than the other.
MONO BRIDGE OPERATION:
Follow these instructions to bridge the unit's outputs. Bridging the amplifier
converts the unit to a monophonic or single channel. The amplifier can be
used with 4Ohm or higher loads only in MONO BRIDGE mode. This
mode is used to provide a higher voltage with greater headroom to your
speaker. Before setting your amplifier for MONO BRIDGE operation,
make sure that your speaker can handle the high power level provided by
the amplifier in MONO BRIDGE mode.
CAUTION: VOLTAGE OVER 100 VOLTS MAY BE PRODUCED AT THE BRIDGE OUTPUT
TERMINALS IN THIS MODE.
1. With the power off, set the OPERATION MODE SWITCH (8) to the
BRIDGE position. When the power is on, the BRIDGE LED (15) on the
front panel will light. If the LED does not illuminate, you have the switch in
the wrong position. Correct before continuing.
2. With the power off, connect your input cables to CHANNEL A input only
using either the XLR INPUT JACK (5) or 1/4" INPUT JACK (7) of
CHANNEL A. The other CHANNEL A input can be used to link to an
additional amplifier.
3. Connect the loudspeaker to the BRIDGE SPEAKER OUTPUT (10) only.
The total speaker load must be at least 4 Ohms or above. 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.
(19, 20) of both channels set to zero (fully
(19, 20) of both channels set to zero (fully
4. With the CHANNEL A LEVEL CONTROL (19) set to zero (fully
counterclockwise), turn the POWER SWITCH (12) ON. With the level
controls of your MIXER or other INPUT device turned all the way DOWN,
turn the amplifier level controls all the way up for desired loudness from
your speakers. Note, when the CLIP LED (17) light, there is distortion
present in the amplifier's output section. If a CLIP LED (17) remains on or
flashes repeatedly, reduce the signal level by lowering the input level
control for CHANNEL A or reduce the level at the source. During MONO
BRIDGE operation, the CHANNEL B level is inactive, however, both
channels LED will flash simultaneously and show output conditions.
5. Now adjust your MIXER or other INPUT source to your desired listening
level. You also have the choice of keeping the volume of both speakers
equal, or for certain situations you can adjust the volume so one side will
be louder than the other.

USING THE SIGNAL GROUND LIFT SWITCH:

Depending on your system configuration, sometimes applying the ground
will create a quieter signal path. Sometimes lifting the ground can
eliminate ground loops and hum to create a quieter signal path.
1. With the power amp on, listen to the system in idle mode (no signal
present) with the ground applied (the SIGNAL GROUND LIFT SWITCH (2)
in the left position).
2. Then turn the power off before moving the SIGNAL GROUND LIFT
SWITCH (2). Lift the ground by moving the SIGNAL GROUND LIFT
SWITCH (2) to the right, turn the power back on and listen to determine
which position will provide a signal devoid of background noise and hum.
Keep the SIGNAL GROUND LIFT SWITCH (2) in the ground position if
the noise level remains the same in either position.
CAUTION: DO NOT TERMINATE THE AC GROUND ON THE POWER AMPLIFIER IN ANY WAY.
TERMINATION OF THE AC GROUND CAN BE HAZARDOUS.

SPECIFICATIONS:

Output Power EIA: 1 kHz @ 1% THD
Single Channel 8Ω
Both Channels Driven 8Ω
Single Channel 4Ω
Both Channels Driven 4Ω
Single Channel 2Ω
Both Channels Driven 2Ω
Mono Bridge 8Ω
Mono Bridge 4Ω
Dynamic Headroom:
8Ω
4Ω
Frequency Response.................................................................20 Hz - 20 kHz
Total Harmonic Distortion...........................................less than 0.01% @ 1 kHz
Intermodulation Distortion.........................................less than 0.02% (SMPTE)
Signal to Noise Ratio.....................................100 dB below rated power @ 8W
Damping Factor (GXA-750)..........................................greater than 500 @ 8W
Damping Factor (GXA-1600)........................................greater than 800 @ 8W
Slew Rate.............................................................................................16 V/mS
Voltage Gain..............................................................................................33 dB
Input Sensitivity (for rated power at 8 Ohm):
Input Impedance Unbalanced............................................................10 kOhms
Input Impedance Balanced................................................................20 kOhms
Power consumption:
NOTE: POWER CONSUMPTION IS GIVEN AT RATED POWER AT 8
PER CHANNEL, BOTH CHANNELS DRIVEN.
AC Power Requirement:
(power connection is factory configured)...................120V/ 60 Hz 230V/ 50 Hz
Indicators:........................................1 Power Indicator, 1 Signal LED per channel,
1 Clip LED per channel, 1 Protect LED per channel, 1 Mono LED, 1 Bridge LED
Cooling:........................................2 Speed Dual Fan; Front-to-Rear Forced Air
Protection:......Short Circuit, DC, Thermal Cut-off, Sub/ultrasonic Frequency Filters,
In-rush Current Limiter, Turn-on Delay, main fuse, secondary DC supply fuses
Connectors:
Balanced/Unbalanced Inputs......................................................1/4" TRS Jack
Balanced Inputs.....................................................................XLR Female Jack
Speaker Outputs........................................Speakons (CH.A, CH.B and bridge)
Dimensions.........................................19" x 13.75" x 3.5" (483 x 350 x 89 mm)
Weight"
SPECIFICATIONS AND DESIGN ARE SUBJECT TO CHANGE
WITHOUT NOTICE FOR PURPOSE OF IMPROVEMENT.
(5)
GXA-750 GXA-1600
190 340
175 300
325 600
275 500
470 950
360 800
550 1000
750 1600
1.3 1.3
2.3 2.1
0.82 V 1.1 V
RMS RMS
550 VA 1000 VA
27 lbs 34 lbs
12.34 kg 15.5 kg