Fostex AP2090 User Manual
OUTSTANDING FEATURES
1) Forced cooling
When the amplifier internal temperature rises, thee cooling
fan automatically changes to high speed to force cool the
heat sink for protecting the amplifier.
2) Level indicator (AP2090, AP2130)
This LED is lit in 5dB steps over the 0 ~ - 30dB range to
check the input signal.
3) Clip indicator
This LED is lit at overload. It will flash on large instant-
aneous inputs but will not pose any problems.
4) Thermal indicator
When this LED is lit, it indicates that the amplifier inter-
nal temperature is unusually high, and the power supply
voltage is reduced automatically to control the amplifier
output.
Consequently, you may notice some distortion when this LED
is lit as the amplifier output has been reduced.
5) Crossover network circuit (AP2090, AP2130)
These contain a 2 way crossover network continuously varia-
ble over 30Hz ~ 2,000Hz at an 18dB/octave slope.
6) Crossover network OUTPUT connector (HIGH, LOW; AP2090 and
AP2130 only)
This output connector allows multi system use with a 2 way
or 3 way speaker system (Refer to Multi System Examples,
page 6) and HIGH PASS/LOW PASS outputs can be obtained from
each output connector.
7) Compressor/limiter circuit
Individual compressor / limiter circuits for each channel are
contained which can be made to function by the rear panel ON
/ OFF selector switch. The limiter can be switched ON / OFF by
the rear panel COMP / L switch. The compressor operates at a
compressinon ratio of 2, from about 1/2 of rated output up to
clipping output, after which the hard limiter functions to
suppress distortion. Consequently, when the limiter is
switched on, the output will not largely distort even at ex-
cess input.
When the amplifier internal temperature rises, thee cooling
fan automatically changes to high speed to force cool the
heat sink for protecting the amplifier.
2) Level indicator (AP2090, AP2130)
This LED is lit in 5dB steps over the 0 ~ - 30dB range to
check the input signal.
3) Clip indicator
This LED is lit at overload. It will flash on large instant-
aneous inputs but will not pose any problems.
4) Thermal indicator
When this LED is lit, it indicates that the amplifier inter-
nal temperature is unusually high, and the power supply
voltage is reduced automatically to control the amplifier
output.
Consequently, you may notice some distortion when this LED
is lit as the amplifier output has been reduced.
5) Crossover network circuit (AP2090, AP2130)
These contain a 2 way crossover network continuously varia-
ble over 30Hz ~ 2,000Hz at an 18dB/octave slope.
6) Crossover network OUTPUT connector (HIGH, LOW; AP2090 and
AP2130 only)
This output connector allows multi system use with a 2 way
or 3 way speaker system (Refer to Multi System Examples,
page 6) and HIGH PASS/LOW PASS outputs can be obtained from
each output connector.
7) Compressor/limiter circuit
Individual compressor / limiter circuits for each channel are
contained which can be made to function by the rear panel ON
/ OFF selector switch. The limiter can be switched ON / OFF by
the rear panel COMP / L switch. The compressor operates at a
compressinon ratio of 2, from about 1/2 of rated output up to
clipping output, after which the hard limiter functions to
suppress distortion. Consequently, when the limiter is
switched on, the output will not largely distort even at ex-
cess input.
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