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Doc. no: 312-0003-002-001 Rev 1.06
What is class “D” amplifier?:
A switching amplifier or class-D amplifier is an electronic amplifier which, in contrast to the active resistance
used in linear mode AB-class amplifiers, uses switching mode of transistor to regulate power delivery. The
amplifier, therefore, features the high power efficiency (low energy losses), which additionally results in lower
weight by eliminating the bulky heat sinks. Additionally, if voltage conversion is necessary, the on-the-way high
switching frequency allows the bulky audio transformers to be replaced by small inductors. Low pass LC-
filtering smoothes the pulses out and restores the signal shape on the load.
What is line level on our amplifier?:
Line level is a term used to describe the strength of an audio signal used to transmit analog sound information
between audio components such as CD and DVD players, TVs, audio amplifiers, and mixing consoles, and
sometimes MP3 players. In contrast to line level, there are weaker audio signals, such as those from
microphones and instruments
pickups,
and
stronger signals, such as those used to
drive headphones and loudspeakers. The strength of the various signals does not necessarily correlate with the
output voltage of a device; it also depends on the source's output impedance, or the amount of current
available to drive different loads.
The most common nominal level for consumer audio equipment is
−
10 dBV
(0,316 V
RMS
), and the most common nominal level for professional equipment is 4 dBV.
Phantom power:
Phantom power (labeled as +48 V on some audio equipment - also +12 V or + 24 V in some applications) is a
method that sends a DC electrical voltage through microphone cables. It is best known as a common power
source for condenser microphones, though many active DI boxes also use it. In Neets Audio Amplifier version 3
we use 24 V
DC
as phantom power.
RS-232 cable connections:
To connect the Audio Amplifier you must wire the RS-
232 cable as shown here to the right. This is a Female
9 pin SUB-D connector, what will fit into a standard
computer RS-232 port, or any USB to RS-232
converter.
RS-232 loopthru:
312-0002 and 312-0003 has the possibility to make
“RS
-
232 loopthru” by this means, if the audio amplifier is connected to one of Neets Control systems (all
systems except Neets Control QueBec) you will get an “extra” RS
-232 port.
You control the audio amplifier thru RS-232 port 1 (connect this port to the control system), and you can
connect (e.g. a projector) to RS-232 port 2 on the audio amplifier. When doing so and setting the system
correct up in the “Neets Product Configurations Software” you will be able to control the audio amplifier and
the projector from one (1) comport on the control system.
Please be aware that the first time you set up the system with a Neets Control system, the power must be
connected to the Neets Control system
AFTER
the Audio Amplifier.
LAN to RS-232 loopthru:
The 312-
0003 has the possibility to make “LAN to RS
-
232 loopthru” by this means that if you use our control
system Neets Control
–
EU, professional (P/N#: 307-0002) and you connect both the Audio amplifier and the
Neets Control
–
EU, professional to a LAN network, you will get additional 3 RS-232 ports to control external
devices (located on the audio amplifier). So by using this function you will, on the Neets Control
–
EU,
professional get in total 5 RS-232 ports, and on top of that have control over the audio amplifier.
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