Crown Audio CSL 1400 - Manual (Page 11)

1400 CSL Power Amplifier
Page 12 Reference Manual
This protection circuitry is activated in unusual situa-
tions where the unit’s transformer temperature rises to
unsafe levels. Under these abnormal conditions, the
unit removes power to the high-voltage transformer (the
fan will also run in 120 VAC, 60 Hz units). The amplifier
will return to normal after it cools to a safe temperature.
It is very unlikely that you will ever see a CSL amplifier
activate transformer thermal protection as long as it is
operated within rated conditions. The amplifier is de-
signed to keep working under conditions where other
amplifiers would fail. But even when the limits of a
CSL
are exceeded, it still protects itself—and your invest-
ment—from damage.
3.3.5 Fuses and Circuit Breakers
The power supplies for the
1400 CSL are protected by
a circuit breaker. With rated loads and output levels,
the circuit breaker should only shut down the amplifier
in the incredibly rare instance of a catastrophic ampli-
fier failure. Other protection systems such as
ODEP
keep the amplifier operational under most other severe
conditions. The breaker can also shut down the ampli-
fier in situations where extremely low-impedance loads
and high output levels result in current draw that ex-
ceeds its rating. Again, this should only be possible
when
operating outside rated conditions, such as driv-
ing a 1-ohm load or overloading the input and creating
a severely clipped signal.
In addition to the breaker, your unit has a separate fuse
for the low-voltage power supply and cooling fan.
A amplifier will not blow its fuse (or breaker) unless
something is wrong. In the rare event that an internal
fuse blows, please refer the unit to a qualified techni-
cian. If the breaker in your amplifier trips, try to identify
and correct the problem before resetting the breaker
with the back panel reset switch. If the problem per-
sists, refer the unit to a qualified technician.
3.4 Controls
The enable switch is located on the front panel so you
can easily turn the amplifier on and off. When making
any setup or wiring changes, don’t forget to turn off the
amplifier, turn down the level controls and disconnect
the power cord. The back panel
stereo/mono switch
is used to select Stereo, Bridge-Mono or Parallel-Mono
operating modes (see Sections 2.1 and 2.2). The
level
controls are also located on the back panel. Be sure
to leave channel 2 turned down when using Bridge-
Mono mode. The back panel
ground lift switch iso-
lates the phone jack input grounds from the chassis
ground to help prevent ground loops. It does not affect
any installed input accessories. The
input sensitivity
switch is located inside the back cover plate. It is used
to set the amplifier’s input sensitivity (see Section 2.3).
The
1400 CSL has a back panel reset switch that is
used to reset the breaker that protects the amplifier’s
power supplies (see Section 3.3.5).
3.5 Filter Cleaning
A dust filter is provided on the unit’s air intake. If it be-
comes clogged, the unit will cool less efficiently and
may produce lower output levels. To clean, remove the
three phillips screws that secure the front grille. Use
mild dishwashing detergent and warm water for best
results. New filters may be ordered from the factory.
Dust filters are not 100% efficient—depending on the
local environment, the internal heat sinks of the ampli-
fier will benefit from periodic cleaning by a qualified
technician. Internal cleaning information is available
from our Technical Support Group.
Fig. 3.1 Back Panel Level Controls
CHANNEL 2
LEVEL CONTROL
CHANNEL 1
LEVEL CONTROL
CH-2
(MONO)
INPUT
CH-1
INPUT
GAIN
0
1
2
3
4
5 6 7
8
9
10
11
12
GAIN
0
1
2
3
4
5 6 7
8
9
10
11
12
INPUT GROUND LIFT
(AFFECTS PHONE INPUTS ONLY.)
LIFT