d&b audiotechnik 40D, Reference Manual

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Operation (Hardware references)
▪ When three amplifiers are operated with a three-phase (120°)
mains supply, the current on the N (neutral) conductor can be
minimized by matching loads and signals between the three
devices.
▪ Keep the supply line as short as possible and its cross section as
high as possible, especially when operating the device at 100
to 127 V. Voltage drop at full load (20/13 A at 115/230 V)
should not exceed 5 %. For reference specifications, refer to the
following table.
Maximum cable lengths for 5 % voltage drop at 3600 W mains power draw
Cable cross section
100 V 120 V 208 V 230 V
1.3 mm 2 - AWG 16
Not permitted Not permitted 21 m/69 ft 25 m/82 ft
1.5 mm
2 Not permitted Not permitted 24 m/79 ft 29 m/95 ft
2.1 mm 2 - AWG 14
Not permitted Not permitted 33 m/108 ft 40 m/131 ft
2.5 mm
2 Not permitted Not permitted 40 m/131 ft 49 m/161 ft
3.3 mm
2
- AWG 12
12 m/39.5 ft 18 m/60 ft 53 m/174 ft 64 m/210 ft
4.0 mm 2
15 m/50 ft 21 m/69 ft 63 m/206.5 ft 78 m/256 ft
5.3 mm
2
- AWG 10
19 m/62 ft 28 m/92 ft 83 m/272 ft 102 m/334.5 ft
6.0 mm 2
22 m/72 ft 32 m/105 ft 95 m/312 ft 116 m/380.5 ft
8.4 mm
2
- AWG 8
31 m/101 ft 44 m/144 ft 133 m/436 ft 162 m/531.5 ft
8.1.6 Generator operation/UPS requirements
To operate the amplifier using a mains generator or uninterruptible
power supply (UPS), observe the following:
▪ With the 40D amplifier the apparent power figure (VA value) is
about the same as the effective power figure (W value).
▪ Use a generator or UPS that can deliver the maximum power
required by the entire system. Assume a short time power draw
of 3 kVA per 40D. This is particularly important when using a
UPS without dedicated short-time overload capability.
▪ Run the generator or UPS at 220 to 240 V, if available. 50 or
60 Hz is not an issue.
8.2 Power amplifiers
The power amplifiers fitted to the 40D utilize Class D technology
similar to a switch mode power supply. Compared to the known
linear amplifier concept (Class A, AB, G or H), Class D power
amplifiers produce less heat and allow for a compact and light-
weight design.
While supplying very high maximum output swing, they maintain
high efficiency with any kind of signal and load and run as cool as
possible. Channels share the same power supply and are thermally
coupled to provide even higher average power figures when
unevenly loaded. TOP/SUB setups and active cardioid subwoofers
are cases of typical use. A sophisticated circuit design decreases
the impact of the load on the amplifier performance and enables a
well defined sound reproduction. A comprehensive set of
protection features individually prevents each channel from
overload and/or damage/fault. Channels that are not affected will
continue to operate, if safely possible.
d&b 40D Reference manual 1.3 en 33