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User Guide
impedance of the cable may be indistinguishable to the amplifier
from a low impedance speaker.
ALWAYS connect the speakers and turn the volume controls
to zero before switching on; do not touch the speaker outputs
whilst the amplifier is running as this could result in electric shock.
Set the input level controls so that the red "peak" LEDs only
illuminate on the loudest peaks when the levels on the mixer are
at their highest setting.
If the amplifier is being asked to produce more power than it
can supply it will 'clip' the signal, and if this happens the red LED
will be illuminated. In this state, the amplifier can produce an
output in excess of 180 Watts per channel at levels of distortion
up to 30%, which could cause damage to speakers. This distorted
signal has a large amount of extra treble which can damage high
frequency units.
If the "peak" indicators are on excessively there is only one
solution: TURN THE VOLUME DOWN.
Choosing loudspeakers.
If the amplifier is likely to be over-driven, then it is advisable to
use speakers which can handle the extra power. Use a 180W 4W
speaker, or, if two 8W speakers are connected to each channel,
they should be rated at 90W each. Using a 120W and a 60W
together may result in damage to the 60W speaker, as they will
each receive 90W. NJD accepts no responsibility for damage
caused to speakers by over-driving.
When choosing loudspeakers, always refer to the RMS rating,
"music power" or "peak music power" ratings which are normally
between two and four times higher than the RMS power
capability, should be ignored. (The MA200 has a Peak Music
Power Output (PMPO) rating of 570 Watts per channel)
When the MA200 is operating normally, the green LED will be
illuminated.
If a fault occurs within the amplifier leading to a DC condition
© N.J.D. Electronics 1997
Operation
MA200
-Page 6-
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