M250
Amplifier Instructions for Use Page 6 of 8
OPERATION
Issue 4: May 2002
OPERATION
Press the
POWER
rocker switch on the
rear panel - the orange
POWER
LED on
the front panel will light confirming that
the unit is ready for use.
Audio Sense Mode
The M250 is now in “audio sense” mode,
and will turn on when an input signal is
detected.
When an audio signal is received the
amplifier will turn on, and the blue
OPER-
ATE
LED will be lit. If there has been no
audio input for about 15 minutes the
amplifier will turn off and the
OPERATE
LED will go out.
The M250 may be turned on or off manu-
ally by pressing the power status button on
the front panel.
When the amplifier has been turned on
manually by the front button it will revert
to “audio sense” mode if there has been no
audio input for about 15 minutes.
When the amplifier has been turned off
manually by the button it will stay off,
even if audio input is present, until there
has been no audio for about 15 minutes,
when it will revert to “audio sense” mode.
If there is an audio input signal present
when mains power is applied to the M250,
it will turn on immediately with the
OPERATE
LED lit.
Trigger Mode
The M250 responds to a “trigger on” con-
trol voltage of between 5 and 12 volts posi-
tive or negative, received via the 3.5mm
TRIGGER IN
socket on the rear panel.
The first trigger pulse received after apply-
ing mains power will turn the amplifier on,
and cancel the “audio sense” mode.
When the amplifier senses a “trigger off”
pulse (return to zero voltage), the amplifier
will turn off.
The M250 may be turned on or off manual-
ly with the front panel button at any time.
When the amplifier has been turned on
manually by the button, it will turn off if it
receives a “trigger on” signal followed by a
“trigger off” pulse.
If the amplifier has been turned off manual-
ly by the button, it will turn on if it receives
a “trigger off” signal followed by a “trigger
on” pulse.
To cancel trigger mode and revert to audio
sense mode, first remove the trigger source.
Then, using the mains switch at the rear of
the unit, turn mains power off and after a
few seconds, back on again.
Audio Adjustment
Select the required audio input source on
your pre-amplifier, and advance the volume
control to obtain the preferred sound level.
