Lab.gruppen C Series 88:4 - Manual (Page 29)

5. Operation and Performance
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C Series C 88:4, C 68:4, C 48:4, C 28:4 and C 16:4 Operation Manual rev 2.2.3
5.6 Front-panel monitoring and adjustments
5.6.1 Level indicators
Four signal/level/clip LEDs per channel are contained on the C Series front panels :
▸ Orange CPL (Current Peak Limiter) flashing indicates signal exceeds the limits of the output devices and
limiting is in effect.
▸ Red VPL/CLIP indicates that the signal has exceeded maximum output voltage. (Maximum voltage is
determined by rear-panel VPL settings.)
▸ Green - 4 dB indicates output signal has reached this level.
▸ Green - 10 dB indicates output signal has reached this level.
▸ Signal / Hi-Imp (Green/red) indicates an output signal above -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 malfunctioning loudspeaker driver. 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 software application.
5.6.2 Level adjust
Step Attenuation Step Attenuation
1 (Min) -Inf. dB 12 -8.7 dB
2 -Inf. dB 13 -7.4 dB
3 -50 dB 14 -6.0 dB
4 -40 dB 15 -4.5 dB
5 -35 dB 16 -2.7 dB
6 -21.5 dB 17 -0.6 dB
7 -21.5 dB 18 -0.3 dB
8 -14.7 dB 19 -0.1 dB
9 -12.9 dB 20 0 dB
10 -11.4 dB 21 (Max) 0 dB
11 -10.0 dB
Level adjust potentiometers (one per channel) are located behind the removable dust-filter cover on the ampli-
fier’s front-panel. It is not possible to adjust the level settings with the cover in place.
The potentiometer’s operational range is 0 dB to -infinity in 31 steps. Attenuation is logarithmic, with 12 o’clock
position being -10 dB. See table to the above 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 potentiometers.