APART MA120, Инструкция по эксплуатации, Страница: 11 / 24

Instruction manual MA120 - MA240
11
Note: emergency vox or emergency switch and the paging contact will
mute all lower priority input signals. MIC A vox will attenuate all lower
priority input signals by 30 dB. This is also known as “voice over circuit”.
The chime can only be activated by closing the paging contact on the
paging mic.
As long as the chime sounds, the paging message will be muted, even if
the chime level is set to the minimum(off) level.
IMPORTANT!
This amplifier relies on convectional cooling. In normal situations,
overheating will not occur due to the class D amplifier topology. Since
there are no cooling fans in the amplifier, make sure the convectional
cooling system can work properly. The unit can be built in a 19 inch rack
system using the included 19 inch brackets, but the ventilation holes
should never be blocked. Therefore, it is absolutely necessary to allow
at least one free rack space or 44 mm above the amplifier. Make sure
the ambient temperature is between 0 and 40°C. Operating the unit
beyond its normal limits may cause overheating. If necessary, use a forced
ventilation system in your mounting rack when the rack holds multiple
amplifiers.
The mains fuse is located in the mains inlet (14). When the fuse is broken,
replace it with a fuse of the same current and voltage rating:
- MA120: T 2 A L / 250 V.
- MA240: T 3.15 A L / 250 V.
For qualified personnel only!
Before using the amplifier for the first time, check the total impedance of
your speaker lines using an impedance meter: temporarily disconnect the
speaker line from the amplifier and measure the speaker line. Minimum
load impedance @ 100 volt must be 41.7 ohms or more. This value
corresponds to 240 watts @ 100 volt.
Minimum load impedance @ 70 volt must be 20.4 ohms. Do not use more
than 1 speaker output at the same time.