Front Panel Monitoring And Adjustments; Level Indicators; Level Adjust; Mute Indication - Lab.gruppen C 68:4 Operation Manual

7.6 front panel monitoring and
adjustments

7.6.1 Level indicators

Four signal/level/clip LEDs per channel are contained
on the C Series front panels :
1. Orange CPL (Current Peak Limiter) flashing
indicates signal exceeds max. output current.
2. Red VPL/CLIP indicates that the signal has
exceeded maximum output voltage. This
activity is governed by the rear panel VPL
settings.
3. Green - 4 dB indicates output signal has reached
this level.
4. Green - 10 dB indicates output signal has
reached this level.
5. Signal / Hi-Imp (Green/red) indicates an output
signalabove -44 dB. If it turns RED, this indicates
that a high impedance ("open" connection) has
been detected at the output. This can be a fault
such as a disconnected cable or the driver is
not functioning properly. However, it could
indicate acceptable high impedance, such as a
sub-bass enclosure with high impedance at a
certain frequency. When the -10 dB signal LED
is on AND the Hi-Imp. LED turns red, then the
amplifier has detected an open load no speaker
is connected).
For more detailed signal level indications use the
DeviceControl editor application.
OPERATION AND PERFORMANCE 7

8.6. Level adjust

Step Attenuation
1 (Min) -Inf. dB
2 -Inf. dB
3 -50 dB
4 -40 dB
5 -35 dB
6 -21.5 dB
7 -21.5 dB
8 -14.7 dB
9 -12.9 dB
10 -11.4 dB
11 -10.0 dB
12 -8.7 dB
13 -7.4 dB
14 -6.0 dB
15 -4.5 dB
16 -2.7 dB
17 -0.6 dB
18 -0.3 dB
19 -0.1 dB
20 0 dB
21 (Max) 0 dB
Level adjust potentiometers (one per channel) are
located behind the removable dust filter cover on the
amplifier's front panel. With the dust cover in place
it is not possible to adjust the level settings.
The potentiometer's operational range is 0 dB to
-Infinity in 21 steps. Attenuation is logarithmic, with
12 o'clock position being -10 dB. See table to the
right with increments.
It is not possible to adjust the individual channel
attenuation from the NomadLink network or
elsewhere on the amplifier.
Use fingers or a screwdriver to adjust the potenti-
ometers.

7.6.3 Mute indication

Individual channel Mute is indicated by illumination
of the two yellow LEDs at the top of the channel's
LED bargraph. Mute/Un-mute can only be performed
from the network using either the NLB 60E and/or
the DeviceControl PC editor.
C Series Operation Manual 1