In order to set the output in bridge mode:
u
parallel the input by pressing on the link button;
u
connect the loudspeaker to just one speakON: 2+ pin is the
positive and the 2– the negative;
u
minimum load impedance shall be 8
Ω
1+
2+
1–
2–
1+
2+
1–
2–
1+
2+
1–
2–
speakON
Single channel mode
connector
speakON
connector
speakON
Single channel mode
connector
(distributed line)
Bridge mode
FIGURE 9:
Loudspeaker wiring;
a) single channel mode, low impedance loudspeaker;
b) single channel mode, high impedance loudspeaker; c) bridge mode.
a
b
c
9 Protection
In order to protect your device and your speakers from
accidental damage, M5000-4 amplifier include an extensive
automatic protection system. In the following sections, potentially
dangerous scenarios and the amplifiers’ corresponding protective
response are explained in detail.
9.1 Turn on/Turn off muting
Class D amplifiers may cause severe speaker damage at power
up due to the high voltage levels at the output stage. In order to
avoid this, the outputs are muted for less than 2 seconds (less
than 5 seconds for DSP models) after turn on. Similarly, turning
off the amplifier can cause the same problem: outputs are muted
immediately at turn off.
9.2
Short circuit protection
Short circuits or very low impedance loads may destroy the
output stage of any amplifier. In order to protect the amplifier
from the dangerously high current surges arising from accidental
output short circuits or low impedance loads, all M series amps
block channel activity when the current drawn from the load rises
above a set value. The channel is muted for 2 seconds after which
the amplifier will unmute the channel and check whether the
current draw is still over the safety threshold. Should this be the
case, the amplifier will mute the channels for another 2 seconds
and the procedure will reiterate. The red “CLIP” LED will be
turned off only when the output current draw will have returned
within safe limits.
9.3
Thermal protection
Outline M5000-4 amplifier have variable speed fans to assist
cooling. If for some reason the cooling system can’t dissipate
the produced heat correctly, a thermal protection system is
automatically activated to avoid permanent damages. Every
channel pair has a temperature sensor on the output stage
heat sink. Two different protection strategies are implemented
depending on the severity of the overheating. In order to protect
internal components, the amplifier may automatically reduce
output power until the internal temperature returns to safe levels.
9.4 Thermal warning
If the heat sink reaches a temperature of approximately 75°C,
the front panel red “TEMP” LED corresponding to the overheated
channel pair turns on to warn the user of a potentially dangerous
thermal event. Output power is reduced to prevent damages to
the output stage.
9.5
Thermal shutdown
If the heat sink temperature rises above 85°C, the thermal
sensing circuitry will mute each power section of each
compromised channel pair. Only after the heat sink has cooled
down to below 75°C the channel pair will automatically unmute
and the red “TEMP” LED will be turned off.
9.6
DC fault protection
In order to protect your speakers from mechanical damage
caused by a DC signal coming from the amplifier’s output, a DC
detection circuit is placed between the amplifier’s output stage
and power supply. If a DC signal or excessive subsonic energy
appears at a channel output an instantaneous protection circuit
will mute the compromised channel pair. The red “CLIP” LED will
turn on to signal that protective measures have been engaged.
The Sound of Big Ideas
Outline s.r.l. - Via Leonardo da Vinci, 56 - 25020 Flero (Brescia) - Italy
Tel. +39-30-3581341 Fax +39-30-3580431 — Web Site: www.outline.it E-Mail: [email protected]
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