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The BOSE 1800 amplifiers have individual power supplies for each
channel. They combine an excellent solidity and reliability with
an excellent performance and protection.
DESCRIPTION
The BOSE 1800 amplifier is designed with two low noise high speed op-amps
per channel, followed by a heat sink mounted bias circuit, to provide precise
temperature compensation; and a full complementary output stage, featuring
ten 200 watt transistors in each channel (2000 watt total dissipation capa-
bility per channel).
The power and drive-transistors are mounted on two heatsinks with "SIL-PADS"
tor superior long life heat transmission.
The "SIL-PAD" is a new product, specially developed tor this purpose and gives
a better heat transmission and has a much langer life than the conventional
method with mica-isolators and silicon paste.
Experience has proved, that af ter some time, by drying of silicone paste,
the heat transmission reduces strongly and power devices are "blown" without
even delivering maximum power.
The "SIL-PAD" prevents such a breakdown.
A 2-speed temperature operated urtra low noise fan is build in for optimal
cooling. With specially designed alruminium profiles, the BaSE 1800 amplifier
is very solid and really capable of handling heavy raad conditions.
FRONT PANEL
The BOSE 1800 amplifier is provided with a led-indication, showing the cause
of trouble or misuse in various situations.
Besides the usual clip-indication, each channel has a led for:
a) heavy overlaad/speaker short-circuit,
b) overheating.
In case, a or b, the leds illuminate, this also means that the specific
protection is working and the amplifier delivers no power into the laad until
the situation is within acceptable limits again.
The BOSE 1800 amplifier also protects your (expensive) loudspeakersystem against
switching peaks or D.C. current. Approximately 3-5 seconds af ter switchingon the
mains power, the laad is coupled to the amplifier. When switching off mains, in
case of mai.ns-failure or D.C. at the output, the load is decoupled very quickly.
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RE AR PANEL
On the rear panel you will find two inputs per channel.
a) One three pin XLR for balanced and unbalanced mode.
b) One phone jack, only for unbalanced mode.
When using the phone jack, pin two of the XLR will automatically be connected
to ground.
If desired, signal ground can be separated from chassis ground, by switching
ground lift.
