MC850 Operations Manual Rev F
Page 18
Table of Contents
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Note that for the – MXZ model, only channels 7 and 8 have the power
allocation feature. Please ensure that the total tapped power for
channels 5 and 6
plus
the power allocated to channels 7 and 8 does not
exceed 200W.
For the – CV model, there is no power allocation section. However, any
channel can support a maximum to 100W total tapped power as long as the total tapped power for each
group
(channels 1-4 and channels 5-8) does not exceed 200W. In practice it is advisable to keep the total
tapped power for the group and the total tapped power for any single channel to 70-80% of the maximum.
7.2.3
Event Log Tab
The following events are recorded in the Event Log.
1.
Entering Standby mode
2.
Entering Run mode
3.
Device/channels renamed
4.
Channels x & y enabled
5.
Channels x and y disabled
6.
Entering Sleep mode
7.
Entering Wake mode
8.
Speaker impedance changed
9.
Power allocation changed
10.
IP Address/mode changed
11.
Overcurrent warning
12.
Overtemp warning
The system clock is set whenever the application program makes a connection to the device. There is no
internal battery (and thus no internal real-time clock), so the power up time defaults to 01/01/2000
00:00:00. The Event Log file may be cleared, saved, or printed by pressing the appropriate button.
7.2.4
Load Test Tab
The MC850 control and reporting application provides a convenient method of testing the amplifier output
loads. It does not continuously monitor load impedance; nor does it measure impedance during the test
process. It is intended to detect significant changes in loads that would indicate a failed speaker or failed
speaker connection. It works by muting the input audio program and injecting an 18kHz test tone, and
comparing the current load on each channel to a set of reference values the user can establish at any time.
This process takes about 3 seconds.
To use this function, connect all low impedance loads, and tap all high impedance speakers to the desired
values. Since there is some temperature dependence, allow the amplifier to temperature stabilize for best
results. Press the “Take Reference Values” button on the Load Test tab. You will hear several clicks as the
channels are cycled through. You will also hear an 18kHz tone. During this process, the application records
the amplifier current draw for each channel. Once these values are set, pressing the “Load Test” button will
rerun the same sequence and report on the variance relative to the reference values. The repeatability is
better than 1%. Taking temperature variation into account, the repeatability is better than 3%.
