LINE CORD
For your safety, we have incorporated a removable 3-wire line (mains) cable with proper grounding
facilities. It is not advisable to remove the ground contact under any circumstances. If it is necessary to
use the equipment without proper grounding facilities, suitable grounding adapters should be used. Less noise
and greatly reduced shock hazard exists when the unit is operated with the proper grounded receptacles.
NOTE: Always turn off the amplifier before making audio connections. As an extra precaution, have the input
attenuator turned down during power-up.
COOLING REQUIREMENTS (GPS 900 and 1500)
These GPS Series amplifiers use a forced-air cooling system to maintain a low, even operating temperature.
Cooling air is drawn by synchronized, variable-speed fans mounted on the back panel, and exhausts through
slots on the front panel. The fans will remain at low speed until internal operating temperature rises above
450C. Make sure that there is enough space around the back of the amplifier to allow air to enter. The normal
operating temperature is 550C. This is a very cool temperature when compared to most amplifier standards.
What this means to you is a noticeable increase in product life. On the GPS 900 and 1500 models, the fans
will turn on simultaneously when temperature activated.
COOLING REQUIREMENTS (All models except GPS 900 and 1500)
These GPS Series amplifiers use a forced-air cooling system to maintain a low, even operating temperature.
Cooling air is drawn by continuously variable speed fans mounted on the back panel, and exhausts through
slots on the front panel. The fan will remain inactive until internal operating temperature rises above 450C.
Make sure that there is enough space around the back of the amplifier to allow air to enter. The normal
operating temperature is 550C. This is a very cool temperature when compared to most amplifier standards.
What this means to you is a noticeable increase in product life.
NOTE: If the amplifier is rack-mounted, do not use doors or covers on the front or back while the unit is
in operation. Whatever type of rack you are using, make sure that heated air can escape freely, and that
there is no resistance to the intake of cool air through the back grill. Intake and exhaust air must flow without
resistance.
INPUT CONNECTIONS
The input connector accepts balanced and unbalanced audio signals. For use with an unbalanced source, tie the
inverting (-) input to ground by installing a jumper to the signal ground connection. If the inverting input is
left floating, a 6 dB loss in gain will result.
SIGNAL MODE CONFIGURATION
GPS Series amplifiers are configured for two-channel (stereo) or bridged mode operation at the input
connectors and via Mode Switch. To send the same signal to both channels, connect the input signal to
Channel Avia the input connector. Run a jumper from the Thru jack of Channel A to the input of Channel B.
Both channels then share Channel A’s input signal, but will operate independently. Speakers are connected as
in two-channel (stereo) mode.
Bridged mode converts the amplifier into a single-channel unit with a power rating equal to the sum of both
channels’power ratings, and at a load rating of twice that of the single-channel rating. In bridged mode, the
channels operate at opposite polarity of each other so that one channel “pushes” and the other “pulls” equally.
Signal is connected to the Channel AInput connector. The speakers are connected only to the designated “+”
output terminals. Never ground either side of the speaker cable when the amplifier is in bridged mode, as both
sides are “hot”. For GPS Series amplifiers, the minimum nominal load impedance in bridged mode is 4 ohms;
this is the equivalent of driving both channels at 2 ohms. Driving loads of less than 4 ohms may activate the
thermal protect circuitry.
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