6
C Series Operation Manual
8 APPENDIX
8.1 Maintenance
During normal operation your C Series amplifier will
provide trouble-free service. 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 serviced
every 3 years purely as a preventative action.
8. 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
editor 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 60E bridge in a
network. Standard RJ45-equipped Cat5 cables are
used throughout. The daisy 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
apply. This is typically a maximum of 80 meters
/ 300 feet between each device. Follow standard
installation procedures for Ethernet. Distances
beyond100 meters may require use of a repeater, a
format converter, or optical cables.
q
: Why is the NomadLink network a closed-loop
topology?
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 Bench test the amplifier
All Lab.gruppen amplifiers are highly advanced
devices which incorporate various features (e.g. VHF
protection and Power Average Limiter) that make it
impossible to verify maximum performance when
performing a standard bench-test with continuous,
full-scale sine-wave signals.
We therefore highly recommend that you take
the time to read our document: “Amplifier
testing procedure”, found at www.labgruppen.com
under Technical Notes, before you bench-test a
Lab.gruppen amplifier.
Summary of Contents for C 68:4
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