Lab.gruppen C C 16 4, C C 28 4, C C 48 4, C C 68 4, C 68:4 Operation Manual

Rev. 2.0.3

Operation Manual

C Series:

Dedicated Installation Amplifiers

• C 68:4

• C 48:4

• C 28:4

• C 16:4

Item no. OM-CS

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 3

2 C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual

1 CONTENTS .................................................................................................................................................2

2

APPROVALS ................................................................................................................................................4

3 WARNINGS .................................................................................................................................................4

3.1 Explanation of graphical symbols ........................................................................................................4

3.1.1 WARNING ................................................................................................................................4

3.1. 2 CAUTION ..................................................................................................................................4

3.2 Important Safety Instructions ..............................................................................................................4

3.3 User responsibility ...............................................................................................................................5

3.3.1 Mains connection grounding ....................................................................................................5

3.3.2 Speaker output hazard ..............................................................................................................5

3.3.3 Radio interference ....................................................................................................................5

3.3.4 Speaker damage .......................................................................................................................5

3.3.5 Maintenance .............................................................................................................................5

4

WELCOME ...................................................................................................................................................6

4.1 Introduction ..........................................................................................................................................6

4.2 Main Features ......................................................................................................................................6

4.2.1 Class TD amplifier and regulated switch-mode p ower supply ................................................. 6

4.2.2 Amplifier gain ...........................................................................................................................6

4.2.3 Voltage Peak Limiter (VPL) .......................................................................................................7

4.2.4 Protection and performance optimization .................................................................................7

4.2.5 NomadLink / Ethernet control and monitoring network ...........................................................7

5 INSTALLATION ...........................................................................................................................................8

5.1 Unpacking ............................................................................................................................................8

5.2 Mounting .............................................................................................................................................8

5.3 Cooling .................................................................................................................................................8

5.4 Operating voltage ................................................................................................................................8

5.5 Grounding ............................................................................................................................................9

6 QUICK GUIDE OVERVIEW .......................................................................................................................10

6.1 Front-Panel overview .........................................................................................................................10

6.1.1 Power on/off and remote switch ............................................................................................10

6.1.2 Front Panel LED’s ...................................................................................................................10

6.2 Rear-Panel overview ..........................................................................................................................11

6.2.1 The DIP-switch features .........................................................................................................11

6.3 NomadLink / Ethernet network setup ................................................................................................12

7 OPERATION AND PERFORM ANCE ........................................................................................................14

7.1 Introduction ........................................................................................................................................14

7.2 Operation precautions .......................................................................................................................14

7.3 Signal flow and headroom .................................................................................................................14

7.3.1 Signal flow blocks ...................................................................................................................14

7.3.2 Headroom, sensitivity and VPL / Gain settings ......................................................................15

7.4 Audio Input and Output connections, setup and features .................................................................16

7.4.1 Balanced / Unbalanced Input connection ...............................................................................16

7.4.2 Output operation and connection ...........................................................................................16

7.4.3 Output bridge mode ...............................................................................................................16

7.4.4 Amplifier Gain .........................................................................................................................17

7.4.4.1 Channel gain / Level (front-panel pots) .......................................................................... 17

7.4.4.2 Amplifier sensitivity ....................................................................................................... 17

7.4.5 Output Voltage Peak Limiter (VPL) .........................................................................................17

7.4.6 Constant Voltage 70 V and 100 V systems setup and operation ............................................ 18

7.4.7 Current Peak Limiter, (CPL) ....................................................................................................18

7.5 Protection, faults and warnings .........................................................................................................18

7.5.1 Int roduction ............................................................................................................................18

7.5.2 Safe Operating Area Detector (SOAD ) ...................................................................................18

7.5.3 Very High Frequency (VHF ) protection ...................................................................................18

7.5.4 DC protection .........................................................................................................................19

7.5.5 High-impedance war ning (open load) ....................................................................................19

7.5.6 Low-impedance protection (shor t circuit) ...............................................................................19

7.5.7 Temperature protection ..........................................................................................................20

7.5.8 Power Average Limiter (PAL) .................................................................................................20

7.5.9 Soft Start ................................................................................................................................20

7.6 Front-panel monitoring and adjustments ...........................................................................................21

7.6.1 Level indicators .......................................................................................................................21

7.6.2 Level adjust ............................................................................................................................21

7.6.3 Mute indication .......................................................................................................................21

7.6.4 Performance, Warning and Fault indicators ............................................................................22

7.7 NomadLink network and DeviceControl Software ............................................................................23

7.7.1 NomadLink network in the amplifiers ....................................................................................23

7.7. 2 Connection and setup .............................................................................................................23

7.7. 3 NomadLink network cable lengths .........................................................................................24

7.7. 4 Ethernet network cable lengths .............................................................................................25

7.7. 5 DeviceControl software .......................................................................................................... 25

8 APPENDIX .................................................................................................................................................26

8.1 M ai nte na nce ......................................................................................................................................26

8.2 FAQ ....................................................................................................................................................26

8.3 Additional documentation ..................................................................................................................27

8.4 Current Draw and Thermal Dissipation specifications .......................................................................28

9 TECHNICAL SPECIF ICATIONS ................................................................................................................30

10 WARRANTY ..............................................................................................................................................31

1 CONTENTs CONTENTs 1

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 5

4 C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual

This equipment co nforms to the requirements of the EMC d irective 89/ 336/EE C, amended by 92/ 31/EEC and 93/ 68/ EEC and the
requirements of the Low Vol tage Directive 73/ 23/EEC , amended by 93/ 68/EEC .

Standards appli ed: EMC Emission EN5 5103-1, E3
EMC Immunity EN 55103-2, E3, with S /N below 1% at normal ope ration level.
Electrical Safet y EN6006 5, Class I

This equipment is tes ted and approved according to th e U.S. safety standard AN SI/ UL 600 65 and Canadian safety s tandard CSA
C22.2 NO. 6 0065. ETL ma de the tests and they are a National ly Recognized Testing Labora tory (NRTL) .

3.1 Explanation of graphical symbols

The lightning symb ol within a triangle is intende d to alert the user to the presence of u n-insulated “dange rous voltage” within the amplifi er’s
enclosure that may be of s ufficient magnitude to co nstitute a risk of electric shoc k to humans.

The exclamation po int within a triangle is intended to a lert the user to presence of impo rtant operating and ser vice instructions in the li terature
accompanying th e product.

3.1.1 WARNING 3.1.2 CAUTION

3.2 Impor tant Safety Instructions

Before using your ampli fier, be sure to carefully read the appli cable items of these operatin g instructions and the safet y suggestions

Ke ep this manual for future reference. 1.
H eed all warnings. 2.
F ollow all instructions. 3.
D o not use this unit near water. 4.
D o not spill water or other liquids into o r on the unit. Do not operate the amp lifier while wet or standing in li quid. 5.
C lean only with dry cloth.6.
D o not block the air intake or exhaust p orts. Install the unit in ac cordance with the instruc tions. 7.
D o not operate the amplifier near heat pro ducing devices such as radi ators, heat regi sters, stoves or other apparatus that produce heat. Always 8.

operate the unit with the chassis grou nd wire connected to the electrical safety ea rth. Do not defeat the safety purpose of a grounding -type plug. A
grounding typ e plug has two pins and a third groundi ng prong. The third prong is provid ed for your safety. If the provided plug d oes not fit into your
outlet, consult an el ectrician for replaceme nt of the obsolete outlet.

C onnect only to AC power outlets r ated 100-120 V or 200 -240 V, 50-6 0 Hz.9.

Do not use this amplifier if the power cord is broken or frayed. Protect the power cord from being walked upon or pinched particularly at the plugs 10.
and the point where it exi ts from the apparatus.
Only use accesso ries specified by the manufa cturer. 11.
The unit is intended to use in a 19” rack. Follow the mounting instructions. When a rack on wheels is used, use caution when moving the loaded 12.
rack to avoid injury fr om tipping over.
Unplug this appar atus during lightning storms or w hen unused for long periods of t ime. 13.
Do not connect an amplifier output in parallel or series with any other amplifier’s output. Do not connect the amplifier output to any other voltage 14.
source, such as bat tery, mains source, or power suppl y, regardless of whether the ampli fier is turned on or off.
Do not run the output of a ny amplifier back into another ch annel’s input.15.
Refer all servicin g to qualified service pe rsonnel. Servicing is re quired when the apparatus ha s been damaged in any way such as :16.

Power-supply co rd or plug is damaged. •
Liquid has been sp illed into the unit•
An object has fall en into the unit•
The unit has been exp osed to rain or moisture•
The unit does not op erate normally•
The unit was droppe d or the enclosure is damaged•

17. Do not remove top or bottom covers . Removal of the covers will expose h azardous voltages. The re are no user serviceable p arts inside and
removal may void the warranty.

18. An experienced user shal l always supervise this profe ssional audio equipment, e specially if inexperienc ed adults or minors are using th
equipment.

19. The mains plug is used as the dis connect device and shall rem ain readily operable. If the a mplifier mains plug is not read ily accessible
due to mounting in a 19” rack, then the mains plu g for the entire rack must be readily o perable.

20. The US National Differe ncescl.16.3 requires that Noma dLinknetwork cables mu st be flame rated VW-1.

2 A PPROVAL s WARNINGs 3

3.3 User responsibility

3.3.1 Mains co nnection groundi ng

Your amplifier must be connected to a
grounded socket outlet.

3.3.2 Speaker o utput hazard

Power amplifi ers are capable of producing

hazardous output voltages. To avoid electrical
shock, do not touch any exposed speaker wiring
while the amplifier is operating. The external wiring
connected to the speaker terminals shall be installed
by a trained and qualifi ed person, or ready-made
leads or cords of appropriate c apacity shall be
used.

3.3.3 Radio in terference

As the amplifier outputs produce high voltage,do

not connect or disconnect speaker cables when
the mains power is on. Also, attach the safety cover
on the speaker terminals for safe operation and to
comply with electrical product approvals.

A sample of this product has b een tested and complies
with the limits for the European Electro Magnetic
Compatibility ( EMC) directive. This equipment has
also been tested and found to comply with the limits
for a Class B digital device, pursuant to Part 15 of
the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference
from electrical equipment. This product uses radio
frequency energy and if not used or installed in
accordance with these operating instructions, may
cause interference to other equipment, such as radio
receivers. However, there is no guarantee that inter­ference will not occur in a particular installation.
If this equipment does cause harmful interference
to radio or television reception, which can be deter­mined by turning the equipment on and off, the user
is encouraged to try to correct the interference by
one or more of the following measures:

Reorient or relocate the antenna.•
Increase the separation between the equip-

•

ment and receiver.
Connect the equipment into an outlet on a •
circuit different from that to which the receiver is
connected .

Check if the affected unit complies with the •
EMC limits for immunity, (CE -labeled). If not,
address the p roblem with the m anufacturer or
supplier. All electrical products sold in the EC must
be approved for immunity against electromag­netic fields, high voltage flashes, and radio inter­ference.
Consult the dealer or an experienced radio/•
TV technician for help.

3.3.4 Speaker d amage

Your amplifier is very power ful and can be

potentially dangerous to both loudspeakers and
humans alike. Many loudspeakers can be easily
damaged or destroyed by overpowering, especially
with the high power available from a bridg ed
amplifier.
Always check the speaker’s continuous and peak
power capabilities.
Even if though the amplifier’s front-panel attenuators
can be used to reduce the gain, it is still possible to
reach full output power if the input signal level is
high enough.

3.3.5 Mainte nance

Fo r saf e an d rel iab le o pera tio n, t he du st c over s be hin d
the front panel as well as the inside of the amplifier
should be cleaned regularly. If the dust filters and
inside are not maintained there will be safety risks.
For example the amplifier can ignite the dust and
a fire will occur due to high internal temperatures.
There is also a risk that the amplifier will malfunction
since the amplifier is dependent of constant airflow
from front to rear. If the dust filters are not clean and
the amplifier malfunctions, any resultant problems
will not be covered by the warranty.

To reduce risk of fire or electr ic shock, do not expose this
apparatus to rain or mo isture.

To reduce the risk of fire or elect ric shock, do not remove
screws. No user-se rviceable parts i nside. Refer servicing to
qualified ser vice personnel

3 WARNINGs

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 7

6 C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual

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 bec ome fully acquainted
with the many configuration options and multiple
layers of protection circuitry.

To fa cil itat e ti mely ins tall ati on an d us e of t his C Ser ies
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 high­quality 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 den­sity.” 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 c ons tant vol tag e (7 0 V / 1 00 V ) mo de. Nom adLi nk,
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

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 possi­bility.

This manual is shipped with C Series ampli­fier models C 6 8:4, 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 :8 X, C 10: 4X a nd C 5: 4X. Refe renc es t o C Se rie s
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 pro­prietary 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 T D amplifier and regula ted switch-

mode power suppl y

Lab.gruppen’s patented Class TD technolog y com­bin es t he ex cept ion al ef fic ienc y of a Cla ss D amp lifie r
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 topolog y. This ensures st able, 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 loudspeak­ers.

4.2.2 Amplifi er 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 loudsp eaker 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 adjust­ment feature makes it easier to achieve an optimal
balance between headroom and noise floor.

4.2.3 Voltage Peak Limi ter (VPL)

The Voltage Peak Limiter (V PL) 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 VP L feature can be set to ensure that neither
temperature nor current limitations are exceeded
before reaching the desired voltage threshold.

4.2.4 Protec tion and performance
optimizatio n

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 interrup­tions, 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 p arameters of amplifier
components.
Temperature pr otection• ensures that the
amplifier will not be damaged by exceeding
thermal limits.

PAL•, (Power Average Limiter) limits the

maximum average power consumption according
to the power supply and mains-breaker capabili­ties.

VHF•, (Very High Frequency) protection

circuits mute the output of the amplifier when
non-dynamic continuous signals above 10 kHz
are detected.

DC protection• ensures destructive DC

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 repor ts 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 NomadLi nk / Ethernet control a nd
monitoring net work

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 60 E 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 redun­dancy 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 opera­tion more convenient. There is no need to create
a star topology using many switches as with, for
example, an Ethernet system. Indiv idual 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
aut oma tic ally cre ate a prec ise pic ture of al l co nne cted
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

WELCOME 4

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 9

8 C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual

for monitoring performance and so lving problems
during operation.

Via Noma dLink, you can monitor all metering d ata
as well as all faults and warning indications simulta­neously. NomadLink also allows you to remotely
control power on and power off, as well as engage
Mute and Solo functions on individual channels.

5.1 Unpacking

Carefully open the shipping carton and check for any
noticeable damage. Every Lab.gruppen amplifier is
tested and inspected before leaving the factory and
should arrive in perfect condition. If any damage
is discovered, please notify the shipping company
immediately. Only the consignee may institute a
claim with the carrier for damage incurred during
shipping. Save the carton and packing materials for
the carrier ’s inspection. Should you ever need to
ship the amplifier, always use the original packaging
materials.

5.2 Mounting

The amplifier is two rack units high ( 2U) and will fit
into a standard EIA 19” rack. The depth is 34 3 mm
(13.5”). The weight is approximately 8, 5 kg (18.75
lbs.) depending on model type.

Free airflow from front-to-rear of the amplifier must
be possible. Therefore, no doors or rack-lids should
be mounted in front of or behind the amplifiers.

Amplifiers m ay be stacked directly on top of each
other. There is no need for spacing in between units,
though this might enable more convenient installation
of cabling on the rear panel.

It is recommended that rear supports be mounted
for maximum long-term stability.

5.3 Cooling

The amplifier uses a forced-air cooling system

with air flow from front-to -rear, maintaining a low
operating temperature within defined limits. Front-to­rear airflow is preferred as cooler air is present at the
front in nearly all installed applications. (This allows
higher continuous power levels without encountering
thermal problems. ) Never at tempt to reverse the
airflow. The amplifier modules require a pressure
chamber between the fans and heatsink, and this
effect functions only in one direction.
Ma ke su re th at t here is an ade qua te ai r su ppl y in f ront
of the amplifier, and that the rear of the amplifier has
sufficient space to allow the exhaust to escape. If
the amplifier is rack-mounted, do not use covers or
doors on the front or rear of the rack.

Should a heat sink overheat, the temperature
sensing circuits will mute the overheating channel.
If the power supply overheats, another sensing
circuit will mute all output channels until the power
sup ply coo ls to safe ope rati ng te mpe ratu re. A n ea rly
warning before shut down will be indicated on the
front-panel LEDs, and a warning will be sent through
the NomadLink network.

Always make sure that the dust-filters behind the
det ach abl e fro nt p anel are c lea n to e nsur e ma ximu m
possible airflow.

If the amplifier malfunctions due to dirty
dust-filters, any required repairs are not
covered by the warranty.

To calculate the maximum heat emission value, when
installing the amplifiers in rooms with an air-conditio­ning system, please refer to the Current Draw and
Thermal Emissions specifications provided in the
Appendix section.

5.4 Operating voltage

The lab el placed to the right of the mains

ca ble o n th e rea r of the a mpli fier ind icat es t he
AC mains voltage for which the amplifier is wired
and approved: 115 V or 230 V. Connect the p ower
cable only to the AC source type referred to on the
label. The warranty will not cover damage caused by
connecting to an incorrect type of AC mains.

Lab.gruppen switch- mode amplifiers use primary
switching. Bec ause the mains power is rectified

directly in front of the transformer, the amplifier is
insensitive to mains frequency. It may be connected
to 50 or 60 Hz sources, and actually will operate on
line frequencies from DC to 400 Hz.

If the power plug mounted at the factory is not
appropriate for your country, it can be removed and
the proper connector wired in its place as follows:

BLACK or BROWN LIVE
WHITE or BLUE NEUTRAL
GREEN or GREEN/ YELLOW EARTH (GROUND)

If you are not 100% confident of your
co mpe tenc e to rep lac e th e m ains plu g, eng age

qualified personnel to do the job.

Once a suitable AC supply is connected, the
amplifier can be turned on using the front-panel
power switch. The amplifier then goes through a
soft-start sequence as it self-checks its circuits. The
fans will blow at high speed before dropping to idle,
and the “power” LED will illuminate.

Inrush power is controlled and limited during “soft
start”, enabling multiple amplifiers to be powered up
simultaneously.

5.5 Grounding

There is no ground lift switch or terminal on the
C Series amplifiers. The signal ground is always
floating, via a resistor, to chassis and therefore the
grounding system is automatic.

In the interests of safety, never disconnect the earth
(ground) pin on the AC power cord.

Use balanced input connections to avoid hum and
interference.

5 INsTALL ATION INsTALL ATION 5

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 11

10 C Series C 68:4, C 4 8:4, C 28:4 and C 16:4 Operation M anual

6 QUICK GUIDE OVERVIEW QUICK GUIDE OVERVIEW 6

The amplifier’s front panel presents the performance
and fault condition indicators, power and remote
switches, and a removable dust-filter cover. Four
level potentiometers located behind the cover
provide individual at tenuation for the four amp lifier
channels. Range is 0 dB to - infinit y. The 12 o’clock
position indicates -10 dB attenuation. A label area is
located beneath the LED display.

To remove the dust-filter cover, loosen the
thumbscrew at the far left. This allows removal of
the dust-filters for cleaning, and provides access to
channel attenuation. The front cover may be made
“tamper resistant” by replacing the thumbscrew
with a Philips head or safety Torx screw. Thread
size is M3.

Never operate the amplifier without the dust

-filters in place.

.

6.2.1 The DIP-s witch features

The following features may be adjusted using the
DIP-switches on the rear-panel of the amplifier.

Gain - Set for all four channels from +23 dB to +44
dB in 3 dB steps.

Option acti ve - Available for future upgrades.

Fan Masked - When on, engages the intelligent fan

feature which lowers fan speed when no signal is
present.

Bridged Mode - Switches the channel pairs (A+ B
and/or C+D ) into bridged mode operation (automatic

-6 dB gain compensation) .

VPL - Voltage Peak Limiter adjustment is
provided for 8 individual levels. Select the set ting
most appropriate for connected speakers. See
Appendix for details.

Mode - Select VPL mode to either Hard or Soft­operation. F or channels driving sub -woofers and
low-frequency dr ivers, it is recommended to use
the Hard setting for optimal operation. For mid- and
high- frequency drivers, always select Soft.

Mains input 115 V

and 230 V operation

(Not selecta ble)

NomadLink

network In and Out

on EtherCon- housed

RJ45 connec tions

DIP-switches

for adjusting key

features

(See below)

3-pole Ph oenix-

type input

connectors

2-pole screw

terminal output

connections

6.2 Rear-Panel overview6.1 Front-Panel overview

Temperature mu te• (Yellow constant)
VHF• (Very H igh Frequency) protection active

( output muted) (Yellow)

Mute• channel via NomadL ink network (2x Yellow)
CPL• (Current Peak Limiter) active (O range flashing),
CPL• constant ( output muted): Lo impedance / Short circuit

detec tion

Fault• (Yellow plus Orange )
VPL• (Volta ge Peak Limiter) active, VPL/ Clip (Red)
4 dB• signal level ( Green)

-10 dB• signal level (Green )

-40 dB• sig nal level (Green),
Hi-Imp• open load detected ( Red)

Bridge mode• operation on (Yellow). Ch. A+ B or C+D

bridge d.

.

Power on (G reen)
PAL (Power Average Limiter) active ( Red)
Option acti ve (Yellow)
Nomad Link network active (Blue).

PAL

When no VPL,
CPL or PAL
indicators are

illuminated,
and the VPL DIP-switch
is set to maximum at the
specified nominal load,
the amplifier channel is
able to deliver maximum
rated output power.

6.1.1 Power on/off and remote switc h

Th e Pow er o n/ off swi tch is lo ca ted o n th e ri ght s ide . A
second switch, labeled “REMOTE,” is located above
the Power switch. When the Remote switch is on, (with
the mains connected and power switch turned on)
the yel low L ED a bove it w ill i llum inat e in dica tin g tha t
ex te r na l p ow er o n/ o ff c om ma n ds fr om th e No ma d Li nk
network connection will switch the amplifier on or
off. When Remote is activated the amplifier will not
switch on until a “Power On” command is received
from the network. When the remote switch is off,
it is not possible to switch amplifier power on or off
using NomadLink network control.

6.1.2 Front-panel LED’s

The front-panel LED area includes the following
indicators per channel:

When the network is c on-

nected, the blue NomadLink

LED will illuminate even

when mains power is not
connected. NomadLink receives
phantom power from the net work
supplied by the NLB 60E.

44dB
41dB
38dB
35dB
32dB
29dB
26dB
23dB

141V*
118V
100V**
85V

71V
59V
50V
42V

*100V

rms

**70V

rms

Ser. N:o

Removed!

SPEAKER OUTPUTS

BALANCED INPUTS

CH D

CH BCH C CH A

WIRING
NORMAL: CLASS 2
BRIDGED: CLASS 3

PUSH PUSH

Must be grounded
Made in Sweden

200-240VAC 50-60Hz :2300W

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 13

12 C Series C 68:4, C 4 8:4, C 28:4 and C 16:4 Operation M anual

6 QUICK GUIDE OVERVIEW

6.3 NomadLink / Ethernet
network setup

Th e amp lifi er in clu des, as a stan dar d fea ture , int ern al
facilities for the NomadL ink monitoring and control
network. A ll features of the NomadLink network
are accessible via a PC running Lab.gruppen’s pro ­prietary DeviceControl software. A single rackspace
NLB 60E NomadLink Bridge & Network Controller, ac­ce pts t he TC P/ IP d ata stre am f rom t he c ompu ter and
converts it to the NomadLink protocols. Even when
no computer is connected, the NLB 60E can initiate
stand-alone power on/off and muting functions, as
well as report any fault or warning conditions.

The PC is connected to the NLB 60E using a
standard Ethernet interface and a crossed Cat-5 cable
(peer-to-peer setup). If a HUB or switch is in the
network, standard “straight” Cat-5 cables must be
used. T he front and rear Ethernet connections on
the NLB 60E can be used individually, but only one
PC at a time running DeviceControl can access the
subnet.

Many newer laptop computers will allow
peer-to-peer connection with the NLB 60E
using a standard “straight” Cat-5 cable in­stead of a crossed cable.

The default fixed TCP/IP address of the NLB 60E is

192.168.1.166. The subnet mask is 255.255.255.0.

For further details, please refer to instructions sup ­plied with the NLB 60E unit.

The NomadLink connections use standard “straight”
Cat-5/ RJ45 equipped cables. For a safer mechanical
connection it is possible to use N eutrik EtherCon
“XLR-type” housings on the cables.

US National Differences cl.16.3 requires
that NomadL ink network c ables must be
rated VW-1.

Th e OU T por t fr om t he NL B 6 0E m ust b e co nnec ted
to the IN port of the first amplifier. T he OUT port
from the first amplifier in turn connec ts to the next
amplifier’s IN port to form a daisy chain The OUT
port on the last amplifier is connected to the IN port
on the NLB 60E to close the loop.

There are electrical limitations to cable
lengths on a Nomad Link network, both in
terms of total cable length in the loop and

between any two devices. Read the
Operation and Performance chapter in this manual,
or the instructions supplied with the NLB 60E, to
ensure the network is configured within these
constraints.

Although the network will function as an

open loop under most circumstances, it is

strongly recommended that the loop be

closed by connecting the l ast amplifier’s
OUT p ort to the NLB 60E’s IN port. Doing so will
improve redundancy and communication speed.

External contact closures and 24 V low/high triggers
ca n be c onn ecte d to GPI c onn ecto rs o n the NLB 60 E
for control of fire -alarm systems or external power
sequencers. For more details read the instructions
supplied with the NLB 60E.

IN OUT

NOMADLINK

IN OUT

NOMADLINK

NOMADLINK

IN OUT

ETHERNET

GENERAL
PURPOSE
INPUT, GPI

ETHERNET

"Crossed" RJ45 cable:

Between NLB 60E and PC.

"Straight" RJ45 cable:
Between Ethernet switch or hub and NLB 60E.

"Straight" RJ45 cables:
Between NLB 60E and amplifiers, and from
amplifier to amplifier in a subunit.

NOTE: Connection can be made to either
the front or rear panel or the NLB 60E.
Although two computers may be connected
to the NLB 60E simultaneously, only one is
allowed access to the subnet at a time.

QUICK GUIDE OVERVIEW 6

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 15

14 C Series C 68:4, C 4 8:4, C 28: 4 and C 16:4 Operation Manual

7.1 Introduction

The following sections provide comprehensive infor­mation 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

Ma ke su re th at t he Po wer swit ch a nd t he Re mot e

•

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.
Make sure that the AC mains voltage is correct •
and matches the voltage printed on the rear-panel
of the amplifier (115 V or 230 V).
Make sure that no signal is present at the input •
to the amplifi er when powering up. This could
produce an unintentionally loud initial volume
from the speakers.

7.3 Signal flow and headroom

7.3.1 Signal flow blo cks

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 e ffe ct me ans that the inpu t st age is al mos t imp os­sible to clip.

Overall amplifier input gain is adjusted using the
input stage DIP-switches. Please note that the gain
setting is global, affecting all four channels. Following
the input stage, the dedicated level control on each
channel allows signal attenuation from 0 dB to minus
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
maximum output voltage and therefore also the
maximum output power. Eight (8 ) different voltage
stages are available using the DIP-switches on the
rear-panel. See table in A ppendix section with VPL
ratings at typical loads.

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 b een 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.

The headroom available through the input stage to
the clip limiter is shown by the dotted lines as +10
dB at 141 V peak and +20.4 dB at 42 V peak. These
lines illustrate the additional signal level that can be
ac cept ed at the inpu t be fore any s ign ific ant d isto rti on
will appear at the input stage.

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 amplifi er 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.

7.3.2 Headro om, sensitivity an d 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. The
following schematics illustrate how the adjusable
VPL and Gain circuitry affect input sensitivity and
output power:

The tab les to the left of the drawing below show
input sensitivity for C 6 8:4 with an 8 ohm load and
141 V peak (max.) and 42 V peak (min.) respectively
for the eight different gain stages between +23 dB
and +44 dB. The resulting output power is displayed
in dBu, Vrms and Watts in the tables to the far right.
Complete input sensitivity tables for all VPL and
Gain settings for all C Series models, can be found
at www.labgruppen.com.

7 OPERATION AND PERFORMANCE OPERATION AND PERFORMANCE 7

C 68:4 V PL and GAIN settings

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 17

16 C Series C 68:4, C 4 8:4, C 28:4 and C 16:4 Op eration Manual

7.4 Audio Input and Output con­nections, setup and features

7.4.1 Balance d / Unbalanced Input c onnection

Two electronically balanced Phoenix-type inputs are
available. Follow the +,– and Ground labels when
connecting the input signal.

If an unbalanced connection is desired this can be
achieved by summing the minus (“COLD”) and
Ground terminals and using the + terminal as the
“HOT” signal. For the best possible performance,
the summing of ground and minus wires should be
done at the source unit end of the cable (e.g. a CD
player).

Four connectors are supplied for attaching cables to
the inputs. The t ype of connector used is: P hoenix
Contacts, Part number MSTB 2,5 /3-STZ-5, 08

When linking the same source signal to
several input channels, be aware that there
is a limit to the number of channels an

output source can “drive”. A typical output
source (e.g. a DSP crossover unit) can drive up to 4
amplifier channels before line-drivers would b e
required to buffer the signal.

7.4.2 Outpu t operation and conne ction

Screw-terminal connectors with + and – poles are
provided at each channel output for connection of
the speakers.

Make sure that the speaker cables are connected
correctly and tightly, and that accurate polarity is
maintained to all speakers in the system.

As the amplifier outputs produce high voltage,

do not connect or disconnect speaker cables
when the mains power is on. Also, attach the safety
cover on the speaker terminals for safe operation
and to comply with electrical product approvals.

7.4.3 Outpu t bridge mode

It is possible to bridge channels in pairs of two (A+B
and C+ D for example). When bridged, the input
source must be connected to input A ( A+B) or C
(C+D ) respectively. Output speaker cables must be
connected to the plus pole on channel A or C and
the minus pole on B or D.

The main benefit of bridging the output is a doubling
of output voltage. Bridging c an be used to turn the
amplifier into a three-channel amplifier with, for
example, 2 x 1200 W and 1 x 2400 W at 4 ohms
uti liz ing t he C 48 :4, or s imp ly to ach ieve an i mpr essi ve
200 Vrms supply per channel.

Most power amplifier designs, when bridged,
automatically introduce a +6 dB input gain boost
which can lead the user to conclude that said
amplifier delivers “more than double the power”
when in bridge mode. This is clearly not the case, as
the gain boost artificially enhances perceived power
at the cost of headroom. The C Series amplifiers
work on globally set constant gain, and automatically
compensate the input gain by -6 dB. For example, if
the amplifier is configured in a three-channel mode,
then the selected gain is maintained from input to
output on all channels.

7.4.4 Amplifi er Gain

All C Series amplifiers feature adjustable input gain.
Th is ve rsa tili ty e nab les t he a mpli fier to a cco mmod ate
a multitude of system configurations with various
input sources and speaker layouts.

Am plifi er g ain is se t glo bal ly fo r al l fou r ch anne ls. The
range is +23 dB to +44 dB in 3 dB steps. Individual
channel fine level adjustment is available using the
potentiometers on the front panel.

The unique adjustable input gain feature of the C
Se ries make s it easi er to att ain the o ptim um b ala nce
between headroom and signal-to-noise ratio in the
signal path. A weak signal at the input might require
the gain to be raised in order to achieve maximum
output power with the lowest signal-to-noise ratio. A
“hot” input signal, however, would require a lowering
of the gain to avoid sending the amplifier into Voltage
or Current clipping.

See A ppendix to review the table containing Gain
versus VPL setting implications for input sensitivity
and output power.

Bridge mode operation automatically
co mpen sat es by -6 dB, keep ing a ll c hann els
at the same gain.

7.4.4.1 Channel gain/ Level (front-panel po ts)

Individual channel gain (level) may be adjusted using
the potentiometers located on the front-panel behind
the dust-filter cover. Range is from 0 dB to -infinity
in 21 steps. The attenuation is logarithmic, with the
12 o’clock position indicating -10 dB.

Use your fingers or a screwdriver to adjust the
potentiometers.

If the level c ontrol is used to attenuate to
a lower level than the headroom relative to
input sensitivity AND the amplifier input is

dri ven into clip , the re i s a da nge r of c lip ping
the input stage before the current or voltage peak
limiters are activated.

7.4.4.2 Amplifier sens itivity

Sensitivity is defined as how many volts ( rms) or
dBu (referred to 0.775 Vrms) are required to achieve
full (maximum) output power. As the output power
varies with the load impedance, 4 ohms is usually

the common reference.

Since C Series amplifiers are capable of providing
multiple maximum output power levels through use
of the VPL feature, many sensitivity calculations may
be required for a single amplifier. We recommend
use of the DeviceControl software to simplify this
process. DeviceControl’s Device View page, used in
combination with the DIP-switch settings display, will
automatically produce a sensitivity calculation from
the given data (VPL, Gain and load ).

7.4.5 Outpu t Voltage Peak Limiter (VPL)

Voltage Peak Limiter ( VPL) is a unique feature in C
Series amplifiers. It is used to select the maximum
power available on each output channel. Eight levels
can be set using the DIP-switches on the amplifier’s
rear-panel.

V

peakVrms

141 100
118 84
100 70
85 60

71 50
59 42
50 35

42 30

The values for VPL are displayed as maximum voltage
pe ak ( V pe ak) . To t rans lat e V p eak i nto Vrms , yo u mu st
divide the Voltage Peak values by 1.41 (see table).

The V PL allows you to set the correct ma ximum
output peak p ower for optimum performance with
the con nec ted s pea kers . Th e co rrec t se tti ng d epen ds
on the system type (low- or high-impedance) and
the spec ific load connected to the channel. Since
each channel can be configured to deliver either
very high voltage peak power OR high current draw
at low impedances, it is important to set the VPL
correctly.

To configure an individual output channel for a
constant voltage system, you simply adjust the
DIP-switches to the desired voltage. However,
when using an output for a low-impedance system
(2, 4, 8 or 16 ohms), then sometimes you need to
adjust the VPL to a lower setting to avoid either

7 OPERATION AND PERFORMANCE OPERATION AND PERFORMANCE 7

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 19

18 C Series C 68:4, C 4 8:4, C 28:4 and C 16:4 Operation M anual

delivering excessively high continuous power to the
sp eake r or o ver heat ing of th e ou tput cha nne l thr oug h
high current draw. For example, with a very “hot”
continuous output signal, the temperature could rise
to a critical level and activate Temp warning or even
Temp Mute. Lowering the VPL setting normally will
solve this situation.

If the Current Peak Limiter is active or indicates low
impedance, lowering the VPL setting can rectify this
situation as well.

7.4.6 Const ant Voltage 70 V and 100 V systems
setup and ope ration

When using C Series amplifiers to drive constant
vol tag e (h igh -im ped anc e) s pea ker s yste ms a t 70 V

rms

or 100 V

rms

, you can in most cases simply connect
the speakers to the amplifier output terminals, select
the correct VPL setting, and place the ampli fier in
service.

7.4.7 Outpu t Current Peak Limiter ( CPL)

The Current Peak Limiter ( CPL) ensures that the
amplifier will not be damaged by trying to deliver
current to the outputs exceeding the physical limits
of the transistors. The CPL keeps the amplifier within
the Safe Operating Area. The CPL is non-adjustable
and has different limit values depending on model
type. The maximum output current values for the
four C Series models are:

C 68:4, 24. 5 A•

rms per channel

C 48:4 , 17. 5 A•

rms per channel

C 28:4, A•

rms per channel

C 16:4, 8.5 A•

rms per channel

CPL activity is indicated by illumination of an orange
LED for each channel on the front-panel. Warnings
also are shown in the DeviceControl software’s
GUI.

A steadily illuminated orange CPL LED indic ates a
short circuit situation (or very low imped ance). The
output will mute for 6 seconds before measuring
the output impedance again. This will continue until
the short circuit is fixed, at which time the output
will automatically un-mute. An input signal must be
present to allow detection of short circuit or low ­impedance conditions.

If the CPL LED is steadily illuminated orange
while the output is muted and the - 4 dB
signal LED is NOT on, then the amplifi er

output is detecting a short circuit or low
impedance condition. The problem can be solved by
checking input and output cables and examining the
state of the loudspeaker load. If there is no short
circuit present, then the c ondition may be rectified
by lowering the VPL or input levels.

If the CPL and -4 dB indicators are lit simultaneously,
then the amplifier is delivering excessive current and
is being forced into a current limiting state ( output
muted).

7.5 Protection, faults and

warnings

7.5.1 Introdu ction

The C Series amplifiers inc orporate a sophisticated
and comprehensive set of protection features. Faults
and warnings are indicated on the front- panel and
reported via the NomadLink network for indication
on the DeviceControl GUI.

7.5.2 Safe Ope rating Area Detec tor (SOAD)

Th e Saf e Op era ting Are a Det ect or ( SOA D) comp are s
output voltage against output current to ensure that
the output transistors are working inside their safe
operating area.

The SOA D provides fault monitoring and input to
the Current Peak Limiter (C PL). The SOAD has no
dedicated indicator, and its operation is revealed only
in conjunction with features such as the CPL.

7.5.3 Very High Freq uency protectio n

All C Series amplifiers include protection circuits
that detect continuous Very High Frequency (VHF)
content in the input signals. The detection begins at
ap prox imat ely 10 kH z and move s up ward s to i ncl ude
ultrasonic signals If VHF signals are detected, the
output will mute for 6 seconds before re-measuring.
Once no continuing VHF signal is detected, the output
un-mutes and returns to normal operation.

This feature recognizes that continuous full-scale VHF

signals do not appear in “natural” sources such as
mus ic. Any s uch sign als can t her efore be c ons ider ed
as a fault when present. VHF protection is essential
for avoiding damage to high frequency drivers.

The V HF protection operational area is dependent
on output power level and frequency. The illustration
below shows a decreasing threshold on the output
power level, starting at ap proximately 10 kHz and
ris ing wit h a - 6 dB slo pe. T his defi nes the V HF p rote c­tion area. When continuous output power above
the threshold line is detected the VHF protection
becomes active.

20 Hz 10 kHz 20 kHz

30 kHz

-6 dB slope

VHF protection
operation area

Max. Peak
output power

Max. Continous
output power

Output
power

Attack time

VHF protection

Slow

Fast

20 Hz 10 kHz 20 kHz

30 kHz

The Att ack time for the V HF protection is increa­singly shorter at higher frequencies. For example, an
ultrasonic continuous signal will cause the outputs to
mute rapidly, where it will take several milliseconds
for a 10 kHz continuous signal to trigger the output
mute. This is shown in the illustration above.

The V HF protection is NOT a limiter and does not
alter the amplifier’s frequency response. It is imple­mented solely to detect continuous VHF content. The
amplifier will always pass VHF peaks at full power,
with no effect on musical “transients”.

The V HF protection is indicated by a yellow LED
on the amplifier front-panel, with output muting for
6 seconds when in action. It is repor ted as a fault
via the NomadLink network on the DeviceControl
GUI.

If you bench test the amplifier using a
continuous, full scale sine-wave input above
10 kHz, the VHF protection will activate and

prevent measurement of full peak output power.
(Output will be muted long before maximum output
power is attained.) To measure the true peak output
power, use a burst signal.

7.5.4 DC prote ction

DC protection is implemented on eac h output
to prevent damage to connected loudspeakers.
DC present at the output will trigger muting and
illuminate the fault LED indicator. A ny DC present
at the output indicates a hardware malfunction that
requires servicing of the amplifier.

7.5.5 High-i mpedance warning (o pen load)

A high-impedance (open load) condition is indicated
when an input signal above approximately -29dB
is detected and no functioning loudspeakers are
connected to the amplifier. The fault in indicated by
a red Sig /Hi-imp LED. The indicator is green when
a valid load is present under the same input signal
conditions

Since the High- impedance detection
initially triggers only when the input signal
rises above -29dB, it might cause the
indicator to first turn green, and then red,

even in situations where no speaker is connected.

7.5.6 Low-imp edance protect ion
(short ci rcuit)

A low- impedance or short circuit fault is detected
when current draw is high (Current Peak Limiter
active) and when, simultaneously, output signal
is low (-4 dB LED does not illuminate). When this
occurs, the amplifier protects the output stage
from damage by muting the output signal and
bypassing the circuits. Indication of this fault is a
constant orange illumination of the Current Peak
Limiter (CPL) LED on the front-panel. The protection
will sequence at 6 second intervals to re- measure
conditions. If the low-impedance fault is no longer
detected, the amplifier will un-mute.

If the CPL turns constant orange, the output
is muted, and the -4dB signal LED is ON,
then the amplifier has gone into maximum

current protection. This situation is caused
by an excessive input signal and is not due to a short
circuit. Turn down the input signal to avoid or
remedy this situation.

7 OPERATION AND PERFORMANCE OPERATION AND PERFORMANCE 7

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 21

20 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

7.5.7 Temperature pr otection

Thermal measurement points are provided on each
output channel as well as on the power supply. If
these sensors detect temperatures above the speci­fied maximums, a high temperature warning will be
indicated by a flashing Temp LED on the front panel.
The warning also will be transmitted to the Device
Control GUI via the NomadLink network.

As the amplifier approaches a thermal protection
threshold, the warning LED sequence will start with
short “on-time” bursts. If the amplifier continues
to overheat and approaches the temperature limit,
the flashing sequence will be defined by longer and
longer on -time bursts until the protection mode is
activated.

If the temperature becomes too high to continue
safe operation, the overheated output channel(s)
will be muted until the temperature returns to an
acceptable level.

Fully active temperature protection (with muting) is
indicated by a constantly illuminated Temp LED. It
will also b e indicated as a fault via the NomadLink
network on the DeviceControl GUI.

Temperature measurements will continue at 6
second intervals. The output will un-mute when the
channel or power supply returns to a safe operating
temperature.

7.5.8 Power Average Limit er (PAL)

The Power Average Limiter (PAL) controls the
current-drawing relationship between the power
supply and the mains inlet. PAL limits the maximum
average power consumption according to the power
supply cap abilities, ensuring that the PSU will not
overload. In addition, in the larger models that
potentially could pull more current from the mains
than the mains fuses are specified to handle (more
than 16 A), PAL limits the amplifier’s maximum
current draw to prevent blowing the mains fuse.

7.5.9 Soft-S tart

High p owered amplifiers with inadequate inrush
limiting can pull considerable current from the
mains at turn-on. This can result in fast acting mains
breakers tripping. Such is not the case with C Series
amplifiers. T he C Series amplifiers have ver y low
inrush power as the capacitors are charged slowly

and in a controlled manner ensuring that breakers
will not trip.

Several amplifiers will, under normal conditions, be
able to be powered up simultaneously. If you do
experience problems powering up multiple amplifiers
simultaneously, use the NomadLink network and the
NLB60E to establish a power sequence with pre-set
delays between the start-up of each subsequent
amplifier.

7.6 Front-panel monitoring and
adjustments

7.6.1 Level indic ators

Four signal/level/clip LEDs per channel are contained
on the C Series front-panels :

Orange• C PL (C urrent 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 d B in dic ates out put s ign al h as re ach ed

this level.

Green• - 10 dB i ndi cat es o utp ut s ign al ha s re ach ed

this level.

Si gna l / Hi -I mp• (Green/red) indicates an output

sig nal abo ve - 44 d B. I f it turn s RE D, th is in dic ate s
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. H owever, it could indicate
acceptable high impedance, such as a sub-bass
enclosure with high- impedance at a certain
frequency. When the -10 dB sign al 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.

7.6.2 Level adju st

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 d B

Level adjust potentiometers ( one per channel) are
located behind the removable dust-filter cover on the
amplifier’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 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 indi vidual channel
attenuation from the NomadLink network or
elsewhere on the amplifier.

Use fingers or a screwdriver to adjust the potenti­ometers.

7.6.3 Mute ind ication

Individual channel Mute is indicated by illumination of
the two yellow LEDs at the top of the channel’s LED
bargraph. If both LEDs are illuminated and all other
indications are normal, then the channel has been
muted by a command from the NLB 60E front-panel
or the DeviceControl application. Otherwise, a Mute
could indicate a fault condition. (See below)

7 OPERATION AND PERFORMANCE OPERATION AND PERFORMANCE 7

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 23

22 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

7.6.4 Perfor mance, Warning and Fault
indicators

Power on/off• (g ree n) i ndi cate s th at m ains pow er

is switched on.

NomadLink •(blue) indicates that the network

is connected. The NomadLink LED will light up
even before the mains power is connected and
swi tch ed on as i t tak es p hant om po wer from the
network cable.

Bridge mode •(yellow) indic ates if t wo chan-

nels are bridged using the DIP-switch on the
rear-panel.

CPL, •Cur rent Pea k Lim ite r (o rang e) , whe n fla sh-

ing indicates the maximum possible current draw
has been reached.
CPL, • Current Peak Limiter (orange), when con -
stant indicates excessive current draw caused
by a short circuit on the output or very low op­erational impedance. When detected, the output
will mute for 6 seconds before re-measuring the
output impedance. This will continue until the
short circuit is removed. CPL remains constant
orange in a fault condition only when an input
signal is present.
Temperature • (yellow) warning is indicated by a
flashing LED. If the amplifier goes into thermal
protect (output muted) the LED illuminates
constant yellow.
VHF, • Very High Frequency protection (yellow),
indicates that potentially harmful continuous high
frequencies have been detected on the input
signal. The output is muted.

PAL•, Power Average Limiter (red), indic ates

that the amplifier is limiting because the power
supply and/ or the mains inlet fuse has reached
maximum capability.

Hardware fault •is i ndi cate d wh en b oth t he CP L

and VHF indicators light up simultaneously. The
amplifier requires servicing before placing back
in operation.

7.7 NomadLink network and
DeviceControl software

7.7.1 NomadLink n etwork in the amplifie rs

All C Series amplifiers are equipped with the pro­prietary NomadLink network interface. This includes
two Ether Con-housed RJ45 connections: one IN
and one OUT.

Use standard straight Cat-5 Ethernet cables with
RJ 45 c onn ecto rs to con nec t the amp lifie r to the N LB
60E or to daisy-chain multiple amplifiers.

It i s ve ry i mpor tan t th at tw o IN or t wo OU T
ports are NEVER connected to each other.
This will cause the NomadLink communi-

cation and DeviceControl software to
exhibit erratic behavior and display inaccurate data.
However, this situation will not damage the
amplifier circuitry.

Up to 60 amplifiers can be connected to one NLB
60E in a daisy-chain or closed lo op.

When the NLB 60E is powered up, the NomadLink
network receives phantom power. This c auses the
blue Nomad Link LED on the amplifier front-panel
and the NomadLink LED on the rear-panel to light
up. Nom adL ink i s ac tive eve n whe n th e amp lifi er h as
mains power disconnected or is not yet powered
up.

The amplifier does not have a stand-by power
supply for the network. The net work is solely
powered from the NLB 60E. Should an amplifier fail
or be inadvertently disconnected from the mains,
network integrity is fully maintained and all amplifiers

7 OPERATION AND PERFORMANCE OPERATION AND PERFORMANCE 7

remain visible on the system.

7.7.2 Connec tion and setup

The No madLink network requires use of an NLB
60E N omadLink Bridge & Network Controller. The
NomadLink network is established by connecting the
NLB 6 0E OUT port to the first amplifier’s IN port.
Then a daisy-chain is established by connecting the
first amplifier’s OUT port to the next amplifier’s IN
port, and so on. If a closed loop network is desired
for improved redundancy (highly recommended), the
last amplifier’s OUT port must be connected to the
NLB 60E’s IN port.

For all connections, straight C at-5 RJ 45-equipped
Ethernet cables should be used.

Optimal NomadLink performance can only
be assured when using Cat-5 cables.
However, as NomadLink is only using two

wires plus ground for communication and
phantom power it is possible to create converters
from RJ4 5 to, for example, XLR connectors using
2-wire shielded cable. The NomadLink network can
then be operated using a stand ard tie- line in a
multicore signal distribution system. See the drawing
opposite for an example of how to create a
converter.

If a ny c abl e for mat or co nne ctio n ot her t han

Cat-5 ( or better) and RJ45 is utilized, net-

work performance may be compromised.

In t his even t La b.gr upp en c ann ot gu ara ntee
that the NomadLink network will be fully opera­tional.

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 25

24 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

7.7.4 Etherne t network cable len gths

The connection between the NLB 60E and your PC
is a standard Ethernet network running the TCP /IP
protocol. Cable distances between NLB 60E and your
PC follow standard rules for Ethernet systems.

Contact your IT expert for more details.

7.7.5 DeviceC ontrol software

DeviceControl is Lab.gruppen’s proprietary software
application for monitoring and controlling networked
C Series power amplifiers. DeviceControl runs on a
Windows P C, which connects via Ethernet to the
NLB 60E. Device Control provides comprehensive
monitoring of amplifier status as well as control of
amplifier power on/ off and individual channel mute
and solo functions.

Please review the DeviceControl Operation Manual
for more detailed information.

OPERATION AND PERFORMANCE 77 OPERATION AND PERFORMANCE

7.7.3 NomadLink n etwork cable leng ths

In situations where the amplifiers and the NLB 60E
will be positioned in different lo cations at some
distance from each other, or where groups of
amplifiers within a single subnet with up to 60 units
will be installed with a distance in between, these
general rules may be considered:

Below are typical examples of NomadLink network
setups:

Rule 1: •
The maximum cable length in between any two
devices may not exceed 300 meters / 980 feet.
Rule 2: •
In a non-closed-loop daisy-chained subnet the
total maximum cable length is 400 meters /
1300 feet.
Rule 3: •
In a closed-loop subnet the total maximum
cable length is 700 meters / 2300 feet.

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 27

26 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

8 APPENDIX

8.1 Maintenance

During normal operation your C Series amplifier will
provide trouble-free ser vice. The only user mainte ­nance required is to periodically vacuum clean the
foam dust filters behind the front grille.

In some extreme cases it may be necessary for
authorized service personnel to clean the inside of
the amplifier. These conditions usually occur after
prolonged use in extreme environments such as
those using “cracked oil” smoke machines. If you
are using your amplifier in a heavy duty application,
it is recommended to have your amplifier ser viced
every 3 years purely as a preventative action.

8.2 FAQ

Following are common questions asked about
Lab.gruppen C Series power amplifiers together with
helpful answers.

Q: What is the input sensitivity of the amplifiers?
A: Input sensitivity is calculated from the amplifier

gain, maximum output voltage and load. As gain and
output voltage is adjustable in C Series amplifiers,
you need to look this information up in a table found in
the Appendix section of this manual. Input sensitivity
also is automatically calculated in the DeviceControl
software application.

Q: What are the maximum cable lengths allowed
when using the NomadLink network?
A: NomadLink uses a daisy-chain topology to
connect amplifiers and an NLB 60 E in a network.
Standard RJ45-e quipped Cat- 5 cables are used
throughout. The d aisy chain may be made into
a closed -loop by connecting a return cable to the
NLB 60E from the last amplifier.

General rules of cable lengths:

The maximum cable length in between any •
two devices may not exceed 300 meters / 980
feet.
In a non-closed -loop daisy-chained subnet •
the maximum cable length is 400 meters / 1300
feet.
In a closed-loop subnet the maximum cable

•

length is 700 meters / 2300 feet.

Exceeding these limits may result in lost contact
with the devices, or loss of phantom powering due
to cable resistance.

Q: How long can cable runs be on the Ethernet
network connecting the NLB 60E to the PC?
A: On the Ethernet side, normal Ethernet cable limits
ap ply. T his is t ypi call y a m axi mum o f 80 mete rs / 300
feet between each device. Follow standard instal­lation procedures for Ethernet. Distances beyond
100 meters may require use of a repeater, a format
converter, or optical cables.

Q: Why is the NomadLink network a closed-lo op
topolog y?
A: Technically speaking, the closed loop is
optional. The purpose of closing the loop is primarily to
provide a secondary path to the amplifiers. If cables
are broken or disconnected in either direction, all
amplifiers still may be addressed by the network.

Q: How can I be sure that no protection circuits or
safety functions interfere with the output signal?
A: If no Clip or Warning LEDs on the front-panel light
up, you can be fully confident that the rated maximum
output power in the full frequency range is available
for your speakers. No limiting or gain-reduction takes
place without a warning or fault indication.

8.3 Additional documentation

In case you didn’t find what you were looking for in
this Operation Manual, check out the website at
www.labgruppen.com, where you can find a
multitude of additional documentation for C Series:
Drawings, technical data sheets, tables with input
sensitivity, background technology briefs and much
more.

APPENDIX 8

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 29

28 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

8.5 Current Draw and Thermal Dissipation specifications

The following tables contain information on measured current consumption as well as calculated heat dissipation
at three st ates: 1) Stand -by/idling; 2) Normal operation (1/8 of rated power); and 3) at extreme heavy duty
operation (Max. power).

8 APPENDIX APPENDIX 8

C 68:4

Level Load Rated power Line Curre nt *2) Watt *1) Thermal Dissipation

115 VAC 230 VAC In Out Dissipated BTU/hr kCal/hr

Standby with remote power o ff via NomadLink 0 0 0 0 0

Powered on, idling. 133 0 133 454 114

Amp (I) Watt

Pink noise (1/8
ra te d p ow er )

8 Ω / Ch. 120 0 x 4

16.0 8.0 11 23 600 523 1784 450

16 Ω / Bridged 2400 x 2

4 Ω / Ch. 170 0 x 4

22.4 11.2 1 578 850 728 248 4 626

8 Ω / Bridged 3400 x 2

2 Ω / Ch. 120 0 x 4

21.2 10.6 1378 600 778 2655 669

4 Ω / Bridged 2400 x 2

100 V / Ch. 16 00 x 4

21.0 10. 5 14 63 800 663 2262 5 70

200 V / Bridged 3200 x 2

Pink noise (1/4
rated power)
*3)

8 Ω / Ch. 120 0 x 4

32.6 16.3 2429 16 00 829 2829 713

16 Ω / Bridged 2400 x 2

4 Ω / Ch. 170 0 x 4

38.8 19.4 26 97 17 00 997 3402 857

8 Ω / Bridged 3400 x 2

4 Ω / Ch. 120 0 x 4

35.2 17.6 2296 1200 1096 3 740 942

8 Ω / Bridged 2400 x 2

100 V / Ch. 16 00 x 4

35.4 17.7 2605 1600 1005 3429 864

200 V / Bridged 3200 x 2

Mains connector, 230 V CE v ersion 16 A, CEE7

Mains connector, 115 V ETL version 20 A / 5-20P

*1) The amplifi er’s PSU operates as a non-r esistive load, so the c alculation “Volts x A mps = Watts” would not be c orrect. Instead, me asured and
specifi ed here is what is known as the “Active Power” in th e amplifi er providing useful, real-wor ld values of power consu mption and heat dissi pation.

*2) Current draw fi gures measured at 230 V. 115 V fi gures are 230 V fi gures multiplied by two.

*3) Figures measure d at maximum power before a mplifi er protection and limiter features are en gaged. Typically thi s is between 1/4 and 1 /3 of rated
power. Note that the max. power c ondition is very ex treme and will not occu r during normal oper ation. Also note that th e mains breaker will not be
tripped even if operati on is in excess of max. rati ngs.

C 28:4

Level Load Rated power Line Curre nt *2) Watt *1) Thermal Dissipation

115 VAC 230 VAC In Out Dissipated BTU/hr kCal/hr

Standby with remote power o ff via NomadLink 0 0 0 0 0

Powered on, idling. 123 0 123 420 106

Amp (I) Watt

Pink noise (1/8
ra te d p ow er )

8 Ω / Ch. 700 x 4

11.6 5.8 727 350 377 1286 324

16 Ω / Bridged 14 00 x 2

4 Ω / Ch. 700 x 4

13.0 6.5 775 350 425 145 0 365

8 Ω / Bridged 1400 x 2

2 Ω / Ch. 300 x 4

9.4 4.7 529 150 379 129 3 326

4 Ω / Bridged 600 x 2

100 V / Ch. 700 x 4

10.4 5.2 663 350 313 106 8 269

200 V / Bridged 140 0 x 2

Pink noise (1/4
rated power)
*3)

8 Ω / Ch. 700 x 4

24.0 12.0 1589 933 656 2237 564

16 Ω / Bridged 14 00 x 2

4 Ω / Ch. 700 x 4

20.8 10.4 1359 700 659 2249 567

8 Ω / Bridged 1400 x 2

4 Ω / Ch. 300 x 4

14.0 7.0 843 300 543 185 3 467

8 Ω / Bridged 600 x 2

100 V / Ch. 700 x 4

21.4 10.7 145 8 933 525 179 0 451

200 V / Bridged 140 0 x 2

Mains connector, 230 V CE v ersion 16 A, CEE7

Mains connector, 115 V ETL version 20 A / 5-20P

*1) The amplifi er’s PSU operates as a non-r esistive load, so the c alculation “Volts x A mps = Watts” would not be c orrect. Instead, me asured and
specifi ed here is what is known as the “Active Power” in th e amplifi er providing useful, real-wor ld values of power consu mption and heat dissi pation.

*2) Current draw fi gures measured at 230 V. 115 V fi gures are 230 V fi gures multiplied by two.

*3) Figures measure d at maximum power before a mplifi er protection and limiter features are en gaged. Typically thi s is between 1/4 and 1 /3 of rated
power. Note that the max. power c ondition is very ex treme and will not occu r during normal oper ation. Also note that th e mains breaker will not be
tripped even if operati on is in excess of max. rati ngs.

C 48:4

Level Load Rated power Line Curre nt *2) Watt *1) Thermal Dissipation

115 VAC 230 VAC In Out Dissipated BTU/hr kCal/hr

Standby with remote power o ff via NomadLink 0 0 0 0 0

Powered on, idling. 123 0 123 420 106

Amp (I) Watt

Pink noise (1/8
ra te d p ow er )

8 Ω / Ch. 1000 x 4

13,8 6,9 945 500 445 1518 383

16 Ω / Bridged 2000 x 2

4 Ω / Ch. 120 0 x 4

17,4 8,7 117 1 600 571 1948 491

8 Ω / Bridged 2400 x 2

2 Ω / Ch. 600 x 4

12,4 6,2 769 300 469 1600 403

4 Ω / Bridged 1200 x 2

100 V / Ch. 900x 4

13,2 6,6 840 450 390 1331 335

200 V / Bridged 180 0 x 2

Pink noise (1/4
rated power)
*3)

8 Ω / Ch. 1000 x 4

28,2 14,1 21 16 1333 783 2670 673

16 Ω / Bridged 2000 x 2

4 Ω / Ch. 1200 x 4

30,6 15,3 2168 1200 968 3303 832

8 Ω / Bridged 2400 x 2

4 Ω / Ch. 600 x 4

21,6 10, 8 13 68 600 768 2620 660

8 Ω / Bridged 1200 x 2

100 V / Ch. 900x 4

26,4 13,2 1827 1200 627 2139 539

200 V / Bridged 180 0 x 2

Mains connector, 230 V CE v ersion 16 A, CEE7

Mains connector, 115 V ETL version 20 A / 5-20P

*1) The amplifi er’s PSU operates as a non-r esistive load, so the c alculation “Volts x A mps = Watts” would not be c orrect. Instead, me asured and
specifi ed here is what is known as the “Active Power” in th e amplifi er providing useful, real-wor ld values of power consu mption and heat dissi pation.

*2) Current draw fi gures measured at 230 V. 115 V fi gures are 230 V fi gures multiplied by two.

*3) Figures measure d at maximum power before a mplifi er protection and limiter features are en gaged. Typically thi s is between 1/4 and 1 /3 of rated
power. Note that the max. power c ondition is very ex treme and will not occu r during normal oper ation. Also note that th e mains breaker will not be
tripped even if operati on is in excess of max. rati ngs.

C 16:4

Level Load Rated power Line Curre nt *2) Watt *1) Thermal Dissipation

115 VAC 230 VAC In Out Dissipated BTU/hr kCal/hr

Standby with remote power o ff via NomadLink 0 0 0 0 0

Powered on, idling. 129 0 129 440 111

Amp (I) Watt

Pink noise (1/8
ra te d p ow er )

8 Ω / Ch. 400 x 4

8.6 4.3 526 200 326 1112 280

16 Ω / Bridged 800 x 2

4 Ω / Ch. 300 x 4

8.2 4 .1 485 150 335 1143 288

8 Ω / Bridged 600 x 2

2 Ω / Ch. n.r.

4 Ω / Bridged n.r.

100V / Ch. 400 x 4

7.6 3.8 463 200 263 897 226

200V / Bridged 800 x 2

Pink noise (1/4
rated power)
*3)

8 Ω / Ch. 400 x 4

16.2 8.1 1046 533 513 174 9 441

16 Ω / Bridged 800 x 2

4 Ω / Ch. 300 x 4

15.2 7. 6 953 400 553 1887 475

8 Ω / Bridged 600 x 2

2 Ω / Ch. n.r.

4 Ω / Bridged n.r.

100 V / Ch. 400x 4

14.4 7. 2 944 533 411 1401 353

200 V / Bridged 800 x 2

Mains connector, 230 V CE v ersion 16 A, CEE7

Mains connector, 115 V ETL version 15 A / 5-15P

*1) The amplifi er’s PSU operates as a non-r esistive load, so the c alculation “Volts x A mps = Watts” would not be c orrect. Instead, me asured and
specifi ed here is what is known as the “Active Power” in th e amplifi er providing useful, real-wor ld values of power consu mption and heat dissi pation.

*2) Current draw fi gures measured at 230 V. 115 V fi gures are 230 V fi gures multiplied by two.

*3) Figures measure d at maximum power before a mplifi er protection and limiter features are en gaged. Typically thi s is between 1/4 and 1 /3 of rated
power. Note that the max. power c ondition is very ex treme and will not occu r during normal oper ation. Also note that th e mains breaker will not be
tripped even if operati on is in excess of max. rati ngs.

C Series C 68:4 , C 48:4, C 28 :4 and C 16:4 Operation Manual 31

30 C Series C 68: 4, C 48:4, C 28 :4 and C 16:4 Operation Manual

9 TEChNICAL sPECIFICATIONs

Following are the C Series technical specifications. These figures are accurate at the time of printing but
please note that all figures are subject to change without notice. For the most accurate and current information
available, please visit www.labgruppen.com.

Model

Number of channels

Peak total output all channels driven

Peak output voltage per cha nnel

Max. output current per c hannel

Max Output Po wer

16 ohms per ch. (all ch.’s driven)

8 ohms per ch. (all ch.’s driven)

4 ohms per ch. (all ch.’s driven)

2 ohms per ch. (all ch.’s driven)

Hi-Z per ch. (all ch.’s driven): 70 Vrms / 100 V peak

16 ohms Bridged per ch.

1)

8 ohms Bridged per ch.

1)

4 ohms Bridged per ch.

1)

2 ohms Bridged per ch.

1)

Hi-Z Bridged per ch.1): 140 Vrms / 200 V peak

Performan ce with Gain :

THD 20 Hz - 20 kHz for 1 W

THD at 1 kHz and 1 dB below clipping

Signal To Noise Ratio

Channel separation (Crosstalk) at 1 kHz

Frequency response (1 W into 8 ohms) +0/-3 dB

Input impedance

Input Common Mode Rejection, CMR

Output impedance @ 100 Hz

Voltage Peak Li miter (VPL), m ax. peak outp ut

VPL, selectable per ch.

3)

VPL, when bridged 3)

1)

Voltage Peak Limiter mode (per ch.)

Gain and Level

Amplifier gain selectable (all channels)

1)

– rear-panel switches

Default gain

Level adjustment (per ch.)

Connecto rs and switch es

Input connectors (per ch.)

Output connectors (per ch.)

Output bridge mode

High pass filter

NomadLink

®

network

Intelligent fans (on/off)

Power on/off and Remote enable on/off

Cooling

General Purpose Outputs (GPO)

General Purpose Inputs (GPI)

Front-panel indicators

Common

Per channel

Power

Operating voltage, 230 V / 115 V nominal

Minimum power-up voltage, 230 V / 115 V

Power Average Limiter (PAL)

2)

Soft-start / Inrush Current Draw

Mains connector

Dimension s (W/H/D)

Weight

Finish

Approvals

Note 1): Automatic -6 dB gain compensation when bridging channels. Ch.’s A+B and/or C+D, E+F, G+H, can be bridged individually.

Note 2): PAL can reduce the maximum output power to keep the power supply operating safely, and/or to prevent excessive current draw tripping the mains breaker. Refer to Operation Manual.
Note 3): For sine waves, peak voltage output values translate to Vrms with the formula V/1.41 = Vrms. E.g. 100 V peak equals app. 70 V peak. Hence, outputs can be set for high-impedance loads without

requiring a transformer.

All specifications are subject to change without notice.

C 68:4 C 48:4 C 28:4 C 16:4 C 20: 8X C 10:8X C 10 :4X C 5:4 X

4 4 4 4 8 8 4 4

6800 W 4800 W 2800 W 1600 W 2000 W 1000 W 1000 W 500 W

141 V 141 V 141 V 141 V

100 V / 70 Vrms 100 V / 70 Vrms 100 V / 70 Vrms 100 V / 70 Vrms

24.5 Arms 17.5 Arms 12 Ar ms 8.5 Arms 8 Arms 5,6 Arms 8 Arms 5,6 Arms

650 W 6 25 W 60 0 W 400 W 250 W 125 W 250 W 125 W

1200 W 1000 W 700 W 400 W 25 0 W 125 W 250 W 125 W

1700 W 1200 W 700 W 300 W 25 0 W 125 W 250 W 125 W

1200 W 600 W 3 00 W n.r

4)

125 W 6 0 W 125 W 60 W

1600 W 900 W 7 00 W 400 W 250 W 125 W 250 W 125 W

2400 W 2000 W 1400 W 800 W 500 W 2 50 W 50 0 W 250 W

3400 W 2400 W 1200 W 600 W 500 W 2 50 W 50 0 W 250 W

2400 W 1200 W 600 W n.r

4)

250 W 125 W 25 0 W 125 W

n.r. n .r. n.r. n .r. n.r. n .r. n.r. n .r.

3200 W 180 0 W 1400 W 800 W 500 W 250 W 500 W 2 50 W

35 dB and VPL: 10 0 V 32 dB and VPL: 100 V

<0.1% <0.1%

<0.05% <0.05%

>112 dBA >112 dBA

>70 dB >70 dB

2.3 Hz - 56 kHz 2.3 Hz - 56 kHz

20 kOhm 20 kOhm

50 dB 50 dB

30 mOhm 48 mOhm

141, 118, 100, 85, 71, 59, 50, 42 V 100, 63, 45, 32 V

282, 236, 200, 170, 142, 118, 100, 84 V 200, 126, 90, 64 V

Hard / Soft Hard / Soft

23, 26, 29, 32, 35, 38, 41, 44 dB 29, 32, 35, 38 dB

35 dB 32 dB

Front-panel potentiometer, 21 position detented from -inf to 0 dB
, hidden behind security panel/dust-filter grille

Front-panel potentiometer, 21 position detented from -inf to 0 dB
, hidden behind security panel/dust-filter grille

3-pin Phoenix, electronically balanced 3-pin Phoenix, electronically balanced

Barrier strip 2-pole screw terminals Barrier strip 2-pole screw terminals

A+B and/or C+D, inputs A and C are input source A+B, C+D, E+F, G+H, inputs A, C, E, G are signal source

- Fixed at 35 Hz, switch able per channel

On board, 2 x RJ4 5 connectors IN and OU T On board, 2 x RJ4 5 connectors, IN and O UT

Yes, depending on presence of output signal Yes, depending on presence of output signal

Individual switc hes on front-panel Individual switc hes on front-panel

Two fans, front-to-rear airflow, temperature controlled speed Two fans, front-to-rear airflow, temperature controlled speed

- Contact Closure types, 2-pole Phoenix

- Contact Closure types, 2-pole Phoenix

NomadLink

®

Network; Power Average Limiter (PAL)2); Power on NomadLink® Network; Power Average Limiter (PAL)2); Power on

Signal present / High-impedance; -10 dB and -4 dB output
signal;Voltage Peak Limiter (VPL); Current Peak Limiter (CPL): Very
High Frequency (VHF); High temperature; Fault; Mute

Signal present / High-impedance; Voltage Peak Limiter (VPL); Current
Peak Limiter (CPL): Very High Frequency (VHF); High temperature;
Fault; Mute

130-265 V / 65-135 V 100-240 V

171 V / 85 V 80 V

Yes Yes

Yes / max. 5 A Yes / max. 5 A

230 V CE: 16 A, CEE7; 115 V ETL: 20 A / NEMA 5-20P IEC Inlet / NEMA 5-15P

W: 483 mm (19”), H: 88 mm (2 U), D: 343 mm (13.5”) W: 483 mm (19”), H: 88 mm (2 U), D: 343 mm (13.5”)

12 kg (26.4 lbs.) 8.5 kg (18.75 lbs.)

Black painted steel chassis with gray painted steel front Black painted steel chassis with gray painted steel front

CE, ANSI/UL 60065 (ETL), CSA C22.2 NO. 60065, FCC CE, ANSI/UL 60065 (ETL), CSA C22.2 NO. 60065, FCC

General

This product is manufactured by Lab.gruppen, and it
is warranted to be free from any defects caused by
components or factory workmanship, under normal
use and service, for a period of six (6) years from
date of purchase from an authorized Lab.gruppen
dealer.

If the product fails to perform as specified during the
warranty period, Lab.gruppen will undertake to repair,
or at its option, replace this product at no charge to
its owner, provided the unit is returned undamaged,
shipping prepaid, to an authorized service facility or
to the factory.

This warranty shall be null and void if the product is
subjected to: repair work or alteration by a person
other than those authorized by us; mechanical
damage including shipping accidents; war, civil insur­rection, misuse, abuse; operation with incorrect AC
voltage, incorrect connections or accessories; opera­tion with faulty associated equipment; or exposure to
inclement weather conditions. Damage due to normal
wear and tear is not covered by the warranty. Units
on which the serial number has been removed or
defaced will not be eligible for warranty service.

Lab.gruppen shall not be responsible for any
incidental or consequential damages. Lab.gruppen’s
responsibility is limited to the product itself.
Lab.gruppen takes no responsibility for any loss
due to cancellation of any events, or rent of replace­ment equipment or costs due to a third party’s or
customer’s loss of profit, or any other indirect cost
or losses however incurred.
Lab.gruppen reserves the right to make changes or
improvements in design or manufacturing without
assuming any obligation to change or improve
products previously manufactured.

This warranty is exclusive, and no other warranty is
expressed or implied. This warranty does not affect
the customer’s statutory rights.

Internationa l warranties

Please contact your supplier or distributor for this
information, as rights and disclaimers may vary from
country to country.

Technical assis tance and servic e

Internationa l

If your Lab.gruppen product requires repair, contact
your Lab.gruppen dealer or distributor, or contact
Lab.gruppen by fax or email to obtain the location
of the nearest authorized service centre.

Factory ser vice

In the event Lab.gruppen produc t requires factor y
service, you may contact Lab.gruppen’s service
department for return instructions and a Return
Authorization number.
Please note for product return:

Use the original packing.1.
Include a copy of the sales receipt, your name, 2.
return address, phone and fax number, email
address and description of the defect.
Mark the Return Authorization number on the 3.
outside of the packing.
Ship the product prepaid to:4.

Lab.gruppen AB
Faktorvägen 1
SE-4 34 37 Kungsbacka
SWEDEN
Phone: [phone]
Fax: [phone]

[e-mail]
www.labgruppen.com

WARRANTY 10

Lab .gruppen ab • Sweden

internationaL contact • info@Labgruppe n.com

uS contact • [e-mail]

www.labgr uppen.com