Alto APM80.1000 Service Manual page 29

The signal noise is requested to be lower than -65dBu.
10. Listening Test
a). Adjust AC voltage, make AC input is equal to 230V; the power supply switch indicates
the 230V position. Connect to the high quality cabinets, connect the signal of the DVD
player to the input of each channel, adjust the LEVEL MAIN and MONITOR LEVEL to the
appropriate volume, operate the switch and knob of each channel respectively (from
minimum to maximum).During the operation, there should be not occurred big sonic
boom, and also doesn't have the noise of turning the potentiometers, the noise of the
listening amplifier output and MAIN output can not bigger than the sample. Turn on the
PHANTOM power (Note: Before turning on the PHANTOM power, you should turn the
MAIN LEVEL and MONITOR LEVEL to the minimum), the noise of the listening amplifier
output and MAIN output can not become bigger (refer to the sample).
b). Adjust the AC voltage, make the AC output is equal to 115V, the power switch indicates
the 115V position, according to the above method to do the Listening Test.
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