d&b D12 Hardware - Manual (Page 10)

3.6. Power supply
The D12 utilizes an autosensing switch mode power supply for mains
voltages 115/230 V, 50 – 60 Hz (Optional 100/200 V) and
overvoltage protection.
Where voltages outside of this range are present, a self-resetting
protective circuit responds quickly to isolate the internal amplifier power
supply leaving only a supervisory circuit to monitor the mains voltage.
The display will clearly indicate the fault and voltage value.
The supervision circuit is self-resetting.
The associated voltage ranges and/or the guaranteed (nominal)
operating ranges are listed in the following table.
Voltage range Status
0 – 98 V Undervoltage
98 – 134 V 110/115/120 V operation
134 – 195 V Undervoltage
195 – 265 V 220/230/240 V operation
265 – 400 V Overvoltage
Tab. 2: Voltage ranges 115/230 V
To prevent the D12 from cycling on and off with fluctuating mains
power supply voltages, the switching thresholds are delayed and about
4% apart from the border of the voltage range (hysteresis).
Voltage range Status
0 – 85 V Undervoltage
85 – 117 V 100 V operation
117 – 170 V Undervoltage
170 – 234 V 200 V operation
234 – 400 V Overvoltage
Tab. 3: Voltage ranges 100/200 V
D12 Amplifier, Hardware manual (4.9 EN) Page 10 of 28