Operation And Performance; Introduction; Operation Precautions; Signal Flow And Headroom - Lab.gruppen C Series C 10 4X Operation Manual

7 OPERATION AND PERFORMANCE

7.1 Introduction

The following sections provide comprehensive infor-
mation on amplifier connection, setup, operation, and
performance. The detailed information included here
is essential to realizing the full functionality of the C
Series amplifiers.

7.2 Operation precautions

Make sure that the Power switch and the Remote
•
switch on the amplifier front-panel are set to
"off" before making any input, output or network
connections, and also before manipulating the
DIP-switches on the rear panel.
This amplifier is equipped with a Universal Power
•
Supply that handles voltages from 100 V to 240
V (+/- 10%) @ 50-60 Hz

7.3 Signal flow and headroom

7.3.1 Signal flow blocks

All C Series amplifiers have the same signal flow
and feature set. The only difference is the amplifier's
maximum output current per channel.
The input stage of all C Series amplifiers has a high
sensitivity to provide ample system headroom. This
in effect means that the input stage is almost impos-
sible to clip.
Overall amplifier input gain is adjusted using the input
stage DIP-switches. Please note that the gain setting
is global, affecting all channels. Following the input
stage, the dedicated level control on each channel
allows signal attenuation from 0 dB to -infinity.
The CPL (Current Peak Limiter) section dynamically
limits the input signal based on three parameters:
sensed current level, feedback from the output stage,
and sensed voltage clip from the VPL (and output
amplifier voltage clip if "Soft Clip" activated). This
ensures that power output is maintained within the
design limits of the amplifier.
The adjustable VPL (Voltage Peak Limiter) sets the
16 C Series C 20:8X, C 10:8X, C 10:4X and C 5:4X Operation Manual
maximum channel output voltage and therefore also
the maximum channel output power. Four (4) different
voltage stages are available using the DIP-switches
on the rear panel.
The sophisticated output section monitors faults
and generates appropriate warnings, which are
displayed on the amplifier front-panel and transmitted
through the NomadLink network. These alerts allow
the operator to adjust system settings and thereby
avoid problems. In the rare event that conditions are
extraordinarily severe, the amplifier will shut down
until the fault or problem setting has been rectified
or adjusted. These sensing circuits are also employed
to feed back voltage and current level information,
via a side chain, to the limiters. Sensing circuits
also transmit local amplifier module temperature
and power supply temperature to the appropriate
protection mechanisms. Read the Protection, Faults
and Warnings section for further details.
7.3.2 headroom, sensitivity and VPL / Gain
settings
The input amplifier and limiter system is designed to
accommodate extremes of performance. Typically,
exceeding maximum input by much as +10 dB will
only result in a 1% increase in distortion.
If you use the level potentiometer in the
signal chain to reduce the level by an amount
greater than the headroom relative to input
sensitivity, AND you drive the amplifier to
clip level, you are in danger of clipping the input stage
before the current or voltage peak limiters are
activated.
When bridging two channels, you must add
6 dB to the input sensitivity to achieve
maximum output voltage due to the
automatic -6 dB gain compensation
inserted by the amplifier.