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7. OPERATION
7.1 Amplifier
1. Prior to switching on, turn the master control and the level controls of the microphone channels to zero to
avoid a possible switching-on noise. The switch on the unit with the power switch. The power indicator
lights up. In case of a possible mains failure switch on the amplifier with the emergency power switch DC
SW.
2. Turn up the master control so that the mixing ration of the three channels MIC PRIORITY, MIC 2, and
AUX/MIC 3 can be adjusted in an optimum way.
3. With the input selector AUX/MIC 3 adjust the channel AUX/MIC 3 to the connected source:
• button pressed: input switched to microphone level
• button not pressed: input switched to line level
4. Adjust the desired volume ratio with the level controls of the channels MIC PRIORITY, MIC 2, and
AUX/MIC 3. In case of an announcement via the microphone channel MIC PRIORITY the level of the
other channels is drastically attenuated thereby increasing the intelligibility of the announcement. After
the announcement, the level of the other channels slowly returns to the original level.
5. Adjust the desired sound with the tone controls. By adjusting the tone controls, the high frequencies
(control TREBLE) and the low frequencies (control BASS) can be boosted or attenuated. With the
controls in mid-position, the frequency response is not affected.
6. Adjust the definite level of the total volume with the master control. The 5-step LED row shows the output
level. An optimum level control is obtained if level values up to 0 dB are shown at average volume. If the
red LED +3 of the LED level meter lights up, slightly turn back the master control.
7. The alarm siren can be switched on and off with the button SIREN:
• button pressed: siren on
• button not pressed: siren off
Summary of Contents for EIO3-50III
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