NAD C 272 - Manual (Page 6)

by the amber LED above the power switch on the front panel. If the
amplifier will not be used for an extended period of time, switch the
VACATION switch to the OFF position.
12. SLEEP/WAKE-SENSE/DEFEAT
The SLEEP/WAKE, SENSE/DEFEAT switch logic controls the
standby/on-state of the amplifier via the presences or absence of audio
signal at the amplifier channel inputs. The SLEEP/WAKE,
SENSE/DEFEAT switch must be in the SLEEP/WAKE position in order to
use this logic. When the SLEEP/WAKE, SENSE/DEFEAT switch is in the
SENSE/DEFEAT position, this logic control is deactivated.
When the switch is in the SLEEP/WAKE position, the C 272 amplifier will
instantaneously turn on from a standby state, sensing any input signal
from any channel as seen by a lit green SENSE LED on the front panel of
the amplifier (approximately above 20mV RMS input). If all of the audio
signals are absent for approximately 5 minutes, the amplifier will switch
automatically to standby condition, with the green SENSE LED off, and
the amber LED over the front panel switch lit.
FRONT PANEL CONTROLS (FIGURE 2)
1. STAND-BY/PROTECTION INDICATOR
Upon switching Power on, the indicator will light up red and after a
short pause turn to green to indicate the amplifier is ready for use.
In cases of serious abuse of the amplifier, such as overheating,
excessively low loudspeaker impedance, short circuit, etc. the
amplifier will engage its Protection circuitry. The indicator will light
up red and the sound will be muted. In such a case, turn the
amplifier off, wait for it to cool down and/or check the speaker
connections, making sure the overall loudspeaker impedance
doesn’t go below 4 ohms or 8 ohms in Bridge Mode. Once the
cause for the protection circuitry to engage has been removed,
switch the amplifier On again.
The diagram below shows the operation of the Stand-
by/protection indicator:
2. POWER ON/OFF
Press this button to switch the amplifier on or off. The Power
On/Standby (No. 1) indicator located just above the power button and
Protection indicator will light up. After a few seconds, the Protection
LED will turn off, indicating that the amplifier is ready for use.
3. TRIGGER INDICATOR
The 12V-TRIGGER LED illuminates green when the amplifier switches
from standby to power on state via the 12V input (refer to “Rear-Panel
Connections”: 12V-TRIGGER INPUT section). Once you turn on the
amplifier via the 12V-IN TRIGGER, only the absence of the 12V can
return the amplifier to standby state.
4. SENSE INDICATOR
The SENSE LED illuminates green when the amplifier senses a signal
greater than 20mV RMS on any of the amplifier inputs refer to “Rear-
Panel Controls and Connections”: SLEEP/WAKE, SENSE/DEFEAT
section). Once you turn on the amplifier via the SLEEP/WAKE sense
logic, only the absence of a signal to all the amplifier’s inputs can return
the amplifier to standby state.
5. SOFT CLIPPING™ INDICATOR
The green SOFT CLIPPING™ indicator shows that the Soft
Clipping™ mode is engaged. Refer also to chapter “Rear Panel
Connections”, section 7; “Soft Clipping™” for more information.
6. BRIDGE MODE INDICATOR
The BRIDE MODE indicator lights up (amber) when the C 272 is
switched to Bridge Mode. Refer also to chapter “Rear Panel
Connections”, section 6, “Bridge Mode” for more information.
GB
6
Green Amber Red
Normal Operation •
Stand-by •
Protection •