User manual

AD-9 Operating Instructions Page 18
Changing the Gain of Your Amplifier: Internal Adjustments!
CAUTION: These servicing instructions are for use by qualified personnel
only. Ensure that Electrical power to the unit is disconnected before
carrying out any maintenance.
Gain settings are changed internally by simple jumper links. Two rows of pins
marked - GAIN A and GAIN B - are situated on the input PCB (PCB751a). A jumper
link sets the gain and the settings are as follows:
Link 1 & 2 gives 32dB gain
Link 2 & 3 gives approx. 36 dB gain
Link 3 & 4 gives 39dB gain = 6dBu/1.5V sensitivity
NOTE: Factory setting is normally link 1 & 2 = 32dB gain.
Setting higher gain does not change the maximum available power but changes the
level of signal input to achieve maximum power. In any case, provided that the input
signal is less than 20dBu/7.7V, the built in limiter circuit will prevent distortion within
the amplifier.
The gain should be set to match the signal from the source, e.g. mixer, controller,
equaliser etc.
Power Requirements
The AD-9 can be supplied for nominal mains voltages of 115V or 230V.
This amplifier will only operate to its very high specification if it is installed
and operated as described in this manual.