Manual-
•
Individual FAULT FLAG ports
are provided for each channel.
º When a fault is detected on power up, the channel or channels affected are not enabled, and the appropriate
front panel fault indicators are lit. A detected fault is re-tested every 10 seconds.
º When a channel develops a fault while operating, the channel shuts down and the output relay is turned OFF.
A detected fault is re-tested every 10 seconds.
º Possible faults include: supply under-voltage, over-voltage, voltage imbalance, output short to ground, output
short to supply, output short to output, clock not running, over safe temperature.
º Channels set to Master, drive the fault flag high when no fault is present. Passive pull down pulls the fault flag
low when a fault occurs or power is lost. Slave channels read the status of the fault flag (see Master/Slave below).
º The fault flag uses 5 volt logic with high-side active drive and passive pull down. No fault = +5V. Fault = 0V.
• Each channel is set for
MASTER (
up
) or SLAVE (
down
) operation
using the rear panel dipswitch.
º Master channels write fault flag status.
º Slave channels read fault flag status.
º The Master setting is used for remote fault reporting and/or automatic redundancy switching control.
º The Slave setting is used for individual channel remote power sequencing or automatic redundancy switching.
• Internal
automatic redundancy switching
is provided (see page Manual-4).
º The primary amplifier channel is set to Master. The backup amplifier chan-
nel is set to Slave. The Master fault flag is wired to the Slave fault flag. If two
different MA 4 amplifiers are involved (recommended), also wire the fault flag
grounds together. Drive Master and Slave audio inputs from the same source,
and set the SENSITIVITY controls the same. Master and Slave front panel
power switches must be ON.
º When a fault is detected on a Master amplifier channel, that channel is shut
down, the output relay is switched to off, internally connecting the load to the
EXTernal amplifier input. The front panel fault indicator is then lit.
º The Slave channel remains in low-power standby (Ready indicator flashing) until a fault is detected (fault flag no longer driven
high by the Master channel). When a fault is detected, the Slave channel performs a self test, switches to run mode, and closes
the output relay (takes about 500 ms). The output of the Slave channel is connected to the EXTernal amplifier input on the
Master channel.
•
Comprehensive front panel metering
is included for each channel:
º Headroom meters are four-segment. The peak signal level is compared to the limit threshold and the difference in dB is dis-
played as remaining headroom. The limiter threshold is adjusted to account for the average load impedance, resulting in load
compensated headroom indication.
º Red Limiter, yellow Compressor and yellow Expander indicators light when the associated dynamics control is active.
º A red Fault indicator lights when a fault is detected
º The green Load indicator is
off
when impedance is above 16 Ω,
on
when impedance is between 2 and 16 Ω and
flashing
when
the impedance is below 2 Ω.
º The green Ready indicator is
off
when the power switch is off,
flashing
when the power switch is on and the unit is in standby
(Slave channel with high fault flag) and
on
when the channel is active.
DIGITAL
AMPLIFIER
dB Headroom
dB Headroom
dB Headroom
dB Headroom
3
6
12
24
Limit
1
Comp
Exp
Fault
Load
Ready
3
6
12
24
Limit
2
Comp
Exp
Fault
Load
Ready
3
6
12
24
Limit
3
Comp
Exp
Fault
Load
Ready
3
6
12
24
Limit
4
ON
Comp
Exp
Fault
Load
Ready
MA 4
Class 2 Wiring
OUTPUTS
Active Low
Use Rane VR 2 or 20 k
Ω
pot
HIGH-PASS
20Hz
40Hz
60Hz
80Hz
ON
4
+ – + –
+ – + –
+ – + –
+ – +
REMOTE LEVEL
4
4
FLAG
3
2
1
FAULT
V r Vc
V r Vc
V r Vc
V r Vc
–
+ – + –
+ – + –
+ – + –
+ – + –
3 2 1
MASTER
SLAVE
COMP
4 3 2 1
1 2 3 4
+ –
+ –
+ –
+ –
V r Vc
V r Vc
V r Vc
V r Vc
+ –
+ –
+ –
+ –
INPUTS
MODE
13
22
dBu
SENSITIVITY
4
3
13
22
dBu
SENSITIVITY
4
2
13
22
dBu
SENSITIVITY
4
1
13
22
dBu
SENSITIVITY
4
EXP ON
3
INT EXT
LOAD
2
INT EXT
LOAD
1
INT EXT
LOAD
4
INT EXT
LOAD
MA 4
ACN 001 345 482
100-240V
500 WATTS
50/60 Hz
COMMERCIAL
AUDIO
EQUIPMENT
24TJ
LISTED
R
C
US
MADE IN U.S.A.
RANE CORP.
For continued
grounding
protection
do not remove
screw
4
3
2
1
ON
4
3
2
1
ON
V r Vc
V r Vc
V r Vc
V r Vc
+ –
+ –
+ –
+ –
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
4 3 2 1
Class 2 Wiring
OUTPUTS
Active Low
Use Rane VR 2 or 20 k
Ω
pot
HIGH-PASS
20Hz
40Hz
60Hz
80Hz
ON
4
+ – + –
+ – + –
+ – + –
+ – +
REMOTE LEVEL
4
4
FLAG
3
2
1
FAULT
V r Vc
V r Vc
V r Vc
V r Vc
–
+ – + –
+ – + –
+ – + –
+ – + –
3 2 1
MASTER
SLAVE
COMP
4 3 2 1
1 2 3 4
+ –
+ –
+ –
+ –
V r Vc
V r Vc
V r Vc
V r Vc
+ –
+ –
+ –
+ –
INPUTS
MODE
13
22
dBu
SENSITIVITY
4
3
13
22
dBu
SENSITIVITY
4
2
13
22
dBu
SENSITIVITY
4
1
13
22
dBu
SENSITIVITY
4
EXP ON
3
INT EXT
LOAD
2
INT EXT
LOAD
1
INT EXT
LOAD
4
INT EXT
LOAD
MA 4
ACN 001 345 482
100-240V
500 WATTS
50/60 Hz
COMMERCIAL
AUDIO
EQUIPMENT
24TJ
LISTED
R
C
US
MADE IN U.S.A.
RANE CORP.
For continued
grounding
protection
do not remove
screw
4
3
2
1
ON
4
3
2
1
ON
V r Vc
V r Vc
V r Vc
V r Vc
+ –
+ –
+ –
+ –
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
4 3 2 1
