ALC2 User’s Manual. Rev. 01
10
4. Installation____________________________________________________
Cooling and ventilation
The ALC2 amplifier uses forced air cooling in order to maintain a low operating temperature. In the ALC2 the cooling air enters at the front and the hot air leaves
the amplifier at the left side. The reason for this is that the air outside the rack is usually cooler than inside, and therefore the amplifiers can run at higher
continuous power levels without thermal problems. Should the amplifier get too hot, the related channel will be protected. When the output devices of the
amplifier reach a temperature of 85 degrees centigrade (185° F), the ALC2 will prevent further temperature rise by shutting down the class-G amplifier stages.
This is indicated by the protect LED blinking. Usually this will reduce the amount of heat produced in the amplifier enough to stop it from overheating. If this is not
the case, when the amplifier reaches 90 degrees centigrade (194° F), the related channel will be muted, and the protect LED will be illuminated constantly.
When the amplifier cools down to a safe value, normal operation is resumed. Make sure that there is an adequate supply of fresh air in front of the amplifier, and
that there is sufficient space in the rack for the exhaust to escape. In order to let the warm air leave the rack unobstructed, the rack must have openings in it of at
least 75 cm
2
per ALC2.
Mains Power
The AC mains voltage for the ALC2 amplifier is stated at the rear of the amplifier near the PowerCon® input. Make sure your local power matches that of the
amplifier. Connecting the ALC2 to the wrong voltage is dangerous and may damage the amplifier. For safety reasons you also must ensure that the AC supply is
properly grounded. The AC current draw is measured according to the IEC 65 safety standard. The normal operating power is measured using pink noise, with
an average power equal to 1/8 of full power. This corresponds to normal music being played to the clip level of the amplifier. The table below shows the AC
current draw for different loudspeaker loads. Make sure your AC power distribution can handle the currents demanded by the amplifiers.
Peak output power per channel:
AC power draw:
Idle:
8
Ω
620 W
450 VA
75 VA
4
Ω
1000 W
675 VA
75 VA
2
Ω
1440 W
1100 VA
75 VA
The AC mains power may not deviate more than +/-10% from the nominal value.
