4
DESCRIPTION
Audison LRx 4.300:
Four channel car power amplifier characterised by excellent musical performances, small size and
outstanding energy reserve.
Its PWM power supply stage is made with two pairs of 70A MOSFETs; it is stabilised and oversize.
Input stage is provided with a special circuit (LNS) which permits the system disturbances rejection,
reducing noise that is usually due to the vehicle electric parts (alternator, electronic injection, etc.),
without altering musical signal quality.
Driver stages are characterised by a very linear circuitry.They have coupled differential transistors and an
A Class complementary voltage amplifier. Power sections have Darlington configuration with high gain
and SOA (Safety Operation Area) BJT TO247. Thanks to its great capacity to supply current, this amplifier
can easily drive even the hardest loads and satisfy whatever power needs. It can give 65W per channel
on 4 Ohm load and 105W per channel at 2 Ohms in continuous mode. Power increases up to 210Wx2 at
4 Ohms in mono (bridged); it is 65Wx2 and 220Wx1 at 4 Ohms in three channel configuration (3-Ch).
Differently from what occurs with other amplifiers, LRx 4.300 is not blocked by protection systems
immediately below 2 Ohms. Its exclusive “Overload Limiter” circuit allows it to go on working, limiting
output power and pointing out how hard the applied load is by the “Limit”LED blinking.
Its big power reserve, its constant control at low frequencies and its exquisite timbre qualities make it an
ideal amplifier to realise systems designed to attain outstanding musical features and very high sound
pressures (SPL).
LRx 4.300 has a bypass subsonic filter (24dB/Oct.) with adjustable frequency, pre-set at 20Hz. It also has a
HI-PASS (12dB/Oct.) and a LO-PASS (12-24dB/Oct.) Butterworth crossover with independent frequencies;
they can be bypassed through a switch under the setting panel, in the amplifier bottom. Another switch
under the setting panel permits to configure the preamplified output (OUT) as additional input (IN B), in
order to accept the source second output for Rear system.
In case LRx amplifiers are used in extremely difficult conditions (very low loads) or in installations where
space is too narrow and their heat sink cooling is not enough, they can be employed together with CLK2
cooling system (optional). It is a system made of two units to apply onto the amplifier sides; each of
them is provided with an electronically controlled fan that allows the amplifier thermal stabilisation (see
“CLK2 – LRx Cooling Kit”).
Protection includes:
• RGP (Resettable Ground Protection) circuit; in case a short circuit occurs between loudspeakers outputs
and car chassis, it detects a high current flow in the pre-input ground and acts by putting the amplifier in
stand-by, protecting its circuitry;
• a device against short circuits and against DC in the outputs, to protect loudspeakers;
• a device that detects the amplifier temperature excessive increase and stops its functioning until
optimal conditions occur again.
Once the causes which implied protection circuits intervention have been checked and solved, the
amplifier is reset by switching it off and on again.
The amplifier is also provided with another general protection which is insured by an internal strip fuse,
very easy to reach.
Optional:
The following devices are available upon request:
1 – Three kits for subwoofer volume remote control:
• VCR01 and VCRAK (analogue and specific for subwoofer);
• VCRDK (digital; it can be used for master volume control or for level control of any ways in a
multichannel system).
2 - CLK2 cooling system.
21
INSTALLATION
CAUTION!
For the system safer protection, we
recommend the use of a strip fuse
on the cable that connects the
battery positive pole to the
amplifier POWER (+) terminal block.
This fuse has to be installed about
10 cm far from the battery; its value
will have to be equal or slightly
higher (+10% approx.) than
consumption @13.8 VDC, according
to the different configurations (see
“Technical features”).
It will have to be equal to the sum of
the values of all fuses in case system
consists of several amplifiers or in
case amplifiers have several fuses.
AMPLIFIER FIXING
ELECTRIC CONNECTIONS
LRx 4.300 FUSE: 30A
