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AP1200 OWNER MANUAL / GUIDE D'OPERATION
In the unlikely event that the AP1200 overheats, the signal will be sporadically cut off and the PROTECT
LED will flash. If further heating occurs, (due to some malfunction), an internal thermal breaker will
interrupt the primary circuit. There is no visible indication of this rare condition. The AP1200 is designed
and tested to operate under “worst case” conditions without shutting down, so if you experience a thermal
shutdown you should check for blocked air flow.
The fan draws air in from the left side and expels hot air through the rear vents. This is compatible with
our other amplifiers and with most installations. Since hot air rises, the heated air forcibly expelled from
the back tends to rise away from the equipment rack. This draws cool air from the floor upwards into the
sides of the rack. (It is much easier to draw air around corners than to blow air around corners.) In some
cases where the rear of the rack is obstructed it may be necessary to install rack fans to aid cooling. If there
are no obstructions, no secondary cooling is required.
The CLIP LEDS on the front panel will visibly indicate any signal excursion beyond the dynamic headroom
of the amplifier.
The AP1200 comes factory-configured to deliver its maximum power into a 2 Ohm load. However, it is
possible to have your AP1200 modified to deliver its maximum power into 4 Ohms. This modification
should only be performed by a Certified Repair Technician. Your dealer can quickly have it done for you.
This feature is intended to be used in fixed installations where the load is known and is not likely to change.
PLEASE NOTE: In this non-standard 4 Ohm configuration, the minimum load per channel is 4 Ohms and
the minimum BRIDGE load is 8 Ohms. Attempting to operate into 2 Ohm loads while in the 4 Ohm
configuration will cause the amplifier to go into current limit, thermal limit, or both.
In the non-standard 4 Ohm configuration, a red LED is glowing and is visable through the hole marked
“STATUS R=4” on the rear panel next to the line cord. This enables a user to determine how the amplifier
is configured.
The POWER specification chart at the back of this manual shows the powers that can be obtained for various
configurations and loads. For most applications you should stay with the 2 Ohm configuration.
The AP1200 represents a significant advance in the art and science of analog power amplifier design. It
incorporates MOSFETS where they should be used - in the driver stage where their tube-like input
impedance and immunity from secondary breakdown helps them drive bipolar output devices with greater
reliability and power. The unique design of the output stage uses four supply voltages. This greatly reduces
internal power dissipation. Rather than switching between the various supply voltages, the AP1200
smoothly directs its output stage to the appropriate supply. The output is thus free of the “glitches” that
plague other multiple supply designs. In fact, due to the proprietary design of the power output section,
THERMAL PROTECTION:
POWER CONFIGURATION:
OTHER DESIGN DETAILS:
CLIP LEDS:
COOLING:
