17
MULTICHANNEL POWER AMPLIFIER V1.1 web
The ON/PROT LED indicates the connection or disconnection of the load from the power
amplifier.
The thermal protection disconnects the load from the power amplifier. This only happens
under the most severe conditions of continuous overload; in such a case, it is essential to localise and
to rectify the cause of this overheating condition. The thermal protection circuit returns automatically to
its normal operation when the power amplifier output transistors drops under the security level,
connecting the load again
.
Each channel of the power amplifier has an independent load protection circuit.
The power amplifier has ON/PROT LED indicators and relay, one per channel pair (stereo).
FAN
The power amplifier includes a thermally controlled system, which continuously regulates the
fan speed depending on the heat energy it has to discharge. This variable speed circuit avoids abrupt
changes of temperature and substantially extents the working life of the components builds in.
At power amplifier turn on, the fan rotates at maximum speed, in order to exhaust the
maximum dust possible. Soon after, the fan's speed drops to normal speed. The power amplifier fan
rotates at maximum speed also, in an overheating situation (when a thermal protection is activated)
so that the heat drops under the security level quickly.
The fan is placed inside the power amplifier, and incorporates some cooling vents in the front
lateral and rear panel for which the air is evacuated, for that reason it is important make sure that the
cooling vents are always free so that the air could circulate with freedom. The amplifier uses one only
fan, so speed is related to any of the 4 (8) channels needs.
LOAD IMPEDANCES
The power amplifiers MULTICHANNEL series, are designed to drive a 4
Ω
or higher load
impedances in INDEPENDENT mode (8
Ω
or higher in BRIDGE Mode), without current limiting.
When the power amplifier is working in BRIDGE mode, the load impedance must be 8
Ω
or
higher, with the same consideration that in INDEPENDENT mode with 4
Ω
load impedance. This is
because in BRIDGE mode, each channel is like driving with the half load impedance.
MAINTENANCE
Periodically, and in a technical service, you must clean the dust and dirt accumulated inside
the power amplifier, especially in the heat sinks, the fan and the cooling vents, with a vacuum cleaner
or with an air-compressor gun. The dirt diminishes considerably the capacity of radiation and
ventilation.
The input attenuators (potentiometers) are sensitive to the dust accumulated, and therefore for
trouble free operation they must be cleaned with an air compressor gun or be changed if necessary.
NOTE:
Equipos Europeos Electrónicos don't recommend the use of spray cleaners because
they could damage the lubricant layer of the potentiometers. Use compressed air to clean them or
replace with similar parts.
