Operation - Adastra A4 User Manual

Operation

When all connections to the amplifier are made, turn all rotary controls down and switch on the power (1)
and the media player display will illuminate.
Turn Bass and Treble controls (10, 11, 23, 24) to the 12 o'clock position (pointing straight up) and turn the
Ch1, Ch2, Ch3 and Ch4 rotary controls (12, 13, 25, 26) up part way for testing.
If a microphone is connected to one of the mic inputs (17, 18) gradually increase the volume control for that
channel (19,20) and speak into the mic until it is heard through the speakers.
Alternatively, play a signal into one of the aux or line inputs (4, 33, 34, 35) and ensure it is selected on the
input selector (9, 22) and turn up its volume control (5, 7, 8) until the signal is heard through the speakers.
The same test applies for the internal media player (see section below) by playing a track or radio station.
Select "MEDIA PLAYER" on the input selector (9, 22) and gradually increase the media player volume (6)
Turn up the Ch1, Ch2, Ch3 and Ch4 volume controls to the maximum required volume level and reduce the
channel volume control if necessary.
The output of each speaker channel is represented on the SIG and CLIP LEDs (14) and care should be
taken that the red CLIP LED is only lit momentarily during use. Anything longer than a short flash of this
LED may be indicating distortion or clipping of the output signal and the output channel volume control
should be turned down.
Any microphones connected should not be able to "hear" the speakers, which can cause feedback (squealing
or howling) and should not be pointed towards the speakers. If this still happens, turn down the volume for
that microphone and adjust Bass and/or Treble EQ controls to reduce the feedback
If the TALKOVER feature (21) is switched on, speaking into the microphone will "override" any audio
playback from the selected stereo Aux, Line or Media input, which will be reduced in volume temporarily.
This allows voice announcements to be heard without interference from the line inputs or media player.
In addition to input and output volume controls, there are Bass and Treble EQ controls (10, 11, 23, 24) to
adjust the tone of the overall output of each pair of outputs. At the 12 o'clock position, these controls apply
no effect to the signal (no boost or cut).
Moving the Bass control clockwise boosts the low frequencies in the audio, whilst moving it anticlockwise will
cut these low frequencies.
Likewise, moving the Treble control clockwise boosts the high frequencies in the audio, whilst moving it
anticlockwise will cut these high frequencies.
Adjust these EQ controls to suit the type of audio signal or compensate for the room acoustics.
To avoid loud pops through the speakers, turn down the Ch1, Ch2, Ch3 and Ch4 volume controls before
powering down.
953.404UK User Manual