Operation Manual
I-Tech HD Series
Power Amplifiers
page 48
I-Tech HD Series
Power Amplifiers
Operation Manual
page 49
8.1 Protection Systems
Your Crown amplifier provides extensive
pro tection and diagnostic capabilities, including
thermal level control, fault indicators, high-pass
filtering, DC protect, AC under/over volt age
protection, inrush limiting, and variable-speed
fans with tachometer feedback. Microprocessor
monitors fans, and signals an error via System
Architect if fans are not operating.
8.1.1 Thermal Level Control (TLC)
If the amplifier becomes too hot for safe
opera tion, the TLC will engage the input
compressor and the clip LED will illuminate. By
compress ing the input, the amplifier will not
generate as much heat and will have a chance to
cool down. The degree of compression is
proportional to the amount of overheating. This
feature allows the show to go on, rather than
having the amplifier shut down, and only occurs
in extreme situations.
8.1.2 Circuit Breaker
If the current draw of the amplifier exceeds safe
limits, this breaker automatically disconnects the
power supply from the AC mains.
8 Advanced Features
8.2 Global Switching Power Sup ply
with PFC
Thanks to its global power supply, the I-Tech
amplifier works anywhere in the world. There’s
no need to reset an AC mains voltage switch,
and no need to order a special model. The amp
will work and meet all specs on 100V - 240VAC,
50/60 Hz.
Crown’s Switching Power Supply minimizes the
amplifier’s weight.
Typical non-switching power supplies require
large, heavy transformers in order to produce
the required power at the output stage. These
transformers must be large to operate at 50 to
60 Hz (standard AC supplied by the power
company).
By contrast, switching power supplies can oper-
ate with a much smaller (and lighter)
trans former because they first convert the AC up
to a much higher frequency, thereby reducing
waste.
Power Factor Correction (PFC) controls how
your amplifier draws current from the AC mains.
Instead of drawing high-magnitude cur rent
spikes that reduce the capacity of your power
distro (and couple noise into other sys tem
components), PFC draws a smooth and quiet
current waveform that is in phase with the mains
voltage waveform. PFC allows you to reduce the
size and weight of your power distri bution and
improve the performance of your signal
processors.
8.3 3rd Generation Class I Cir cuitry
Class I (BCA, Balanced Current Amplifier)
Interleave technology allows high levels of
power output without all the associated heat
found in a conventional amplifier. This highly
efficient design also provides accurate,
uncol ored sound with very low distortion and a
high damping factor for tight, clean bass
response. And it can deliver more power to
reactive loads than conventional dissipative
designs (com fortably driving the latest high-
technology transducers). Class I also reduces
current draw of the AC mains, providing energy
conserva tion.
8.4 Color-Coded Rear Overlay
The labels on the rear panel are color coded to
group similar functions under common colors.
9 Appendix A: Network and CobraNet Basics
Figure 9.1 A HiQnet Network
9.1 HiQnet Networks
Background
:
A
Local Area Network (LAN)
is a group of computers in a venue that
share data, either through cables or via wireless transmission.
Ethernet
is a popular
LAN communication protocol for PCs. An
audio network
is a Local Area Network
made of audio devices and one or more computers. A
subnet
is a small network within a
larger network. For example, an audio network might have two subnets: one for
enter tainment audio, and one for paging.
One use of an audio network is to control and monitor power amplifiers on stage from a
computer at Front-of-House. You can set amplifier levels, adjust crossovers, measure
speaker impedance, check for overheating and clipping, all from the house mixing
con sole.
You need a way to send computer commands to several audio devices at once. This is
done with an
Ethernet switch
, which is something like an audio Y cable or distribu tion
amp. The computer, and all the audio devices, connect to the switch as in Figure 9.1.
HiQnet
protocol lets you control and monitor cer tain Harman products (including
Crown) on an Ethernet network. Figure 9.1 shows a typical HiQnet network.
HiQnet control offers many advantages:
•
Use of “off-the-shelf” network hardware.
HiQnet uses standard hardware
commonly used in the computer industry, making it both low-cost and readily available.
•
Better Performance.
Meters display faster in realtime because the network is wide
bandwidth.
HiQnet provides these functions:
•
Quickly find all HiQnet components connected to the network.
•
Synchronize multiple control points on a network.
•
Control and monitor components on different Local Area Networks (LANs) through the
use of an IP router (explained later).
•
Upgrade firmware via the network.
Network Addresses
Each component in a HiQnet network has three addresses to identify it:
•
Media Access Control (MAC) Address
•
Internet Protocol (IP) Address
•
HiQnet Address
Let’s explain each identifier.
Computer
Laptop
100Mb Switch
I-T5000HD
I-T5000HD
I-T9000HD
I-T9000HD
I-T12000HD
Содержание I-T12000 HD
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