Lab.gruppen C Series C 16 4 Operation Manual page 4

4 WELCOME
4.1 Introduction
Thank you for choosing Lab.gruppen C Series power
amplifiers for your sound reinforcement system
installation. We are confident that you will be
very pleased with the performance, configuration
flexibility, reliability, and long-term durability offered
by the C Series products.
This manual provides a comprehensive guide to the
features and functionality of C Series model C 68:4,
C 48:4, C 28:4 and C 16:4 amplifiers. Please read
through it in its entirely to become fully acquainted
with the many configuration options and multiple
layers of protection circuitry.
To facilitate timely installation and use of this C Series
product, we have included a Quick Guide Overview
(section 6). This brief summary, in conjunction with
Installation (section 5), contains the basic information
needed to safely install the amplifier and place it in
service. However, we highly recommend reading
through this manual in its entirety, beginning with
Main Features and Technologies and continuing
through Operation and Performance. As you become
thoroughly familiar with all aspects of operation, you
may learn of features or options that will affect your
choices on amplifier modes or loudspeaker system
configuration.
Lab.gruppen C Series power amplifiers are designed
and built specifically for the unique demands of
permanent installation applications. C Series
amplifiers offer the optimum combination of high-
quality audio reproduction, flexible features, ease of
installation, and 100% reliability in normal use.
By packing four or eight channels of reconfigurable
power amplification into a 2U chassis, the C Series
achieves unprecedented "power and channel den-
sity." The benefits of compact dimensions include
reduced rack space requirements and minimal heat
build-up. The flexible output stages enable each
amplifier channel to be set for either low impedance
or constant voltage (70 V / 100 V) mode. NomadLink,
an easy-to-use network for monitoring and control,
is implemented as a standard feature on all C Series
amplifiers.
Although C Series features and facilities are tailored
6 C Series C 68:4, C 48:4, C 28:4 and C 16:4 Operation Manual
to installation applications, at the heart of each
amplifier is the same advanced technology that has
made Lab.gruppen the benchmark of quality for touring
concert systems: exceptional sonic performance,
rugged construction, proven reliability, and protection
features that anticipate every unwelcome possi-
bility.
This manual is shipped with C Series ampli-
fier models C 68:4, C 48:4, C 28:4 and C
16:4. All references to "C Series" in this
manual apply to all four of these models.
A different manual is shipped with models C 20:8X,
C 10:8X, C 10:4X and C 5:4X. References to C Series
in this document may or may not apply to these C...X
models.
4.2 Main features
Thank you again for placing your confidence in Lab.
gruppen power amplifiers.
Your new C Series amplifier incorporates a number
of sophisticated technologies – many of them pro-
prietary to Lab.gruppen – that are provided to ensure
the best possible performance and many years of
reliable operation. Familiarizing yourself with these
technologies will prove invaluable in setting up and
optimizing your loudspeaker system.
4.2.1 Class Td amplifier and regulated switch-
mode power supply
Lab.gruppen's patented Class TD technology com-
bines the exceptional efficiency of a Class D amplifier
with the high sonic quality associated with Class B
designs. Class TD also incorporates the same basic
concepts behind Class H designs, but here they are
refined and pushed to a higher level to achieve much
greater efficiency.
The Class TD output sections work in concert with
Lab.gruppen's unique, regulated switch-mode power
supply (R.SMPS) to create a superior overall power
amplifier topology. This ensures stable, full output
power over an extremely wide range of mains voltage
levels. Sagging or fluctuating mains voltage will not
affect the power output delivered to the loudspeak-
ers.
4.2.2 Amplifier gain
For greater flexibility in system integration, C Series
amplifiers allow gain adjustment from +23 dB to +44
dB in 3 dB steps. This feature accommodates any
combination of input device and loudspeaker type.
For example, if the input signal is weak, the gain can
be boosted to maintain maximum power output while
avoiding a poor signal-to-noise ratio. This gain adjust-
ment feature makes it easier to achieve an optimal
balance between headroom and noise floor.
4.2.3 Voltage Peak Limiter (VPL)
The Voltage Peak Limiter (VPL) feature allows user
adjustments that determine maximum voltage output,
thus matching the amplifier to the connected speaker
load. Whether the connected load is low impedance
(2 to 16 ohms) or high impedance (70 V / 100 V),
the VPL feature can be set to ensure that neither
temperature nor current limitations are exceeded
before reaching the desired voltage threshold.
4.2.4 Protection and performance
optimization
Appropriate and reliable power amplification is vital
to any audio system. Inadequate or faulty power
amplification could cause damage to the loudspeakers,
or in some cases to the power amplifiers themselves.
To prevent any damage or costly service interrup-
tions, C Series amplifiers offer advanced features
to protect both internal circuits and any connected
loads. These features even protect the mains fuse
that, in extreme cases, could be overloaded.
Following are short descriptions of standard built-in
C Series protection features:
• CPL , (Current Peak Limiter) ensures that the
amplifier's output does not exceed the safe
current handling parameters of amplifier
components.
• Temperature protection ensures that the
amplifier will not be damaged by exceeding
thermal limits.
, (Power Average Limiter) limits the
• PAL
maximum average power consumption according
to the power supply and mains-breaker capabili-
ties.
, (Very High Frequency) protection
• Vhf
circuits mute the output of the amplifier when
non-dynamic continuous signals above 10 kHz
are detected.
• dC protection ensures destructive DC
C Series C 68:4, C 48:4, C 28:4 and C 16:4 Operation Manual 7
WELCOME 4
signals will not appear at the amplifier outputs.
If such conditions occur an internal fuse opens
and fault indication is displayed.
• Low impedance (short circuit) protection
provides a fault warning indication and shuts
down the output stage when, for example, an
input signal is present and a malfunctioning cable
or driver is short circuiting the output.
• high impedance warning reports an alert
when, at the same time, output signal is high
and no current draw is measured. This situation
might occur when no speakers are connected,
or when a driver is blown.
• Low inrush current ensures that the
mains breaker will not trip when several power
amplifiers are turned on simultaneously.
4.2.5 NomadLink / Ethernet control and
monitoring network
The NomadLink network allows easy setup and
control of C Series power amplifiers and other devices.
The patented network topology allows automatic
detection and addressing of multiple amplifiers, and
is controlled from a PC via an NLB 60E NomadLink
Bridge & Network Controller using standard TCP/
IP communication. Phantom powering through the
network cables allows the software to detect devices
that are not currently turned on or connected to the
mains. This ensures very high reliability and redun-
dancy levels while allowing connected amplifiers to
remain on standby with no power consumption.
Cable connections can be daisy-chained for easier
system setup. This also reduces total component
costs, simplifies installation, and makes daily opera-
tion more convenient. There is no need to create
a star topology using many switches as with, for
example, an Ethernet system. Individual amplifier
addresses do not need to be manually entered: you
will automatically know where an individual amplifier
resides in the network.
A daisy chain network-loop, in combination with
the automatic addressing of devices, enables
Lab.gruppen's proprietary DeviceControl software to
automatically create a precise picture of all connected
devices and their relative position in the chain. By
quickly creating a clear overview of the entire system
configuration, DeviceControl provides flexible control
over very large amplifier systems. Set-up time is
minimized, and critical information is readily available