APA-4E8 Operator’s Manual
Page 33
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Amp Channel Loads
In addition to the more obvious 24 bit 96k analogue to digital converters (ADCs) fitted to the
inputs of your amplifier for analogue signal conversion, your APA has has eight additional
ADCs of the same quality fitted directly at the output terminals. These are used to monitor
the speaker output voltages and currents in real time and are fed directly back into the DSP,
so near-instantaneous monitoring of power and distortion can be realised. This hardware
addition is crucial to the adaptive nature of your APA.
It also permits real time monitoring of the load impedances using this metric display.
The first time this user metric display is shown after power up, it will display “---“ in place of
a measured impedance, until voltage and current data at a sufficient level has been collected.
This may take a few seconds, and the measurement algorithm is weighted to respond to
instantaneous drops in impedance so that over current protection can operate quickly to
prevent damage to output circuitry.
If the level on any channel drops below the threshold for accurate readings to be taken, the
pervious value will be held and shown in parenthesis as below, where channels 2 and 4 reads
are now not live.
