– This section is labelled “Channel-A” and features a gain control knob (“Gain”), a
crossover selector switch (“LPF / FULL / HPF”), and the variable crossover filter frequency control knob
(“Freq.”). The changes made here affect the speaker(s) connected to the Channel A output.
Gain - Turning the gain knob to the right (clockwise) will increase the volume, and to the left (anti-clockwise)
will reduce the volume. It is important to understand that the amount of gain needed is proportional
to the level of the signal coming from the source unit. For example, it is possible for the gain knob
to be at only a quarter of its maximum, but the amplifier is actually outputting to its full potential.
This could be because the source unit is supplying slightly more power than normally expected.
Please see “Installation” section for how to calibrate the amplifier to the output of the source unit using the
gain knob.
Crossover (“X-Over”) - The crossover switch has three settings, “LPF” (Low Pass Filter), “FULL” (No filter
applied / off) and “HPF” (High Pass Filter). If either the LPF or HPF are selected, the “Freq.” knob (variable
crossover filter frequency) is used to fine tune the filter. The knob controls the frequency at which the
attenuation starts.
Low Pass Filter – This filter lets low frequencies through, and cuts out high frequencies and should be used
when connecting subwoofers to the output. This will cut out high frequencies that the subwoofer(s) are not
designed to reproduce, and so only output the bass from the signal. The Frequ. knob controls the highest
frequency range that is sent to the subwoofer(s). The range is adjustable, from 50 to 500 Hz with a slope of
40 dB per octave. The value that this should be set to changes depending on the subwoofer(s), enclosure and
vehicle used. This can be set by starting with the knob position fully clockwise, then turning the knob anti
clockwise very slowly until the best result is heard. This may take some time to get exactly right. It is
advisable to play music of the genre that will most commonly be listened to as this is set. It is also advisable
to use different tracks when configuring the LPF.
When set correctly, the subwoofer is able to work more efficiently, and the upper frequency range reproduced
is configured to the equipment, surroundings and user taste.
High Pass Filter – This filter lets high frequencies through, and cuts out low frequencies and should be used
when connecting full range speakers such as 6”x9” speakers to the output. This will cut out sub/low bass
frequencies that the speakers can not reproduce at high volumes, and so allow the speakers to operate more
efficiently. The Frequ. knob controls the lowest frequency range that is sent to the speakers. The range is
adjustable, from 50 to 500 Hz with a slope of 40 dB per octave. The value that this should be set to changes
depending on the speakers used. This can be set by starting with the knob position fully anti clockwise, then
turning the knob clockwise very slowly until the best result is heard. This may take some time to get exactly
right. It is advisable to play music of the genre that will most commonly be listened to as this is set. It is also
advisable to use different tracks when configuring the HPF.
When set correctly, the speakers are able to work more efficiently, and the lower frequency range reproduced
is configured to the equipment, surroundings and user taste.
“FULL” – No filter is applied when the switch is set to “FULL”; the full range of frequencies are reproduced and
output to the speakers. In other words the filters are OFF.
2. Channel B Controls - This section is labelled “Channel-B” and operates in exactly the same way as the
above Channel A controls. The changes made here affect the speaker(s) connected to the Channel B output.
3. Indicators
Power indicator - This LED will light when power, remote and earth are all connected to the amplifier. If this
LED is not on, there is a problem with one of these connections.
Protection Indicator - This LED will light if the amplifier has detected a fault and if it is not already damaged,
has shut down to protect itself from permanent damage. This may be due to one of the following: low
voltage, excessive heat, short circuit or overload. If this happens disconnect the amplifier and investigate the
problem.
4. Speaker connections – This section is labelled “Speaker” and consists of Channel A outputs (left and right)
and Channel B outputs (left and right) and are in the form of screw terminals for attaching the speaker cables.
Undo the screw head enough to slot a stripped end of speaker cable into the terminal, and then tighten the
screw. Please see wiring diagrams in the “Installation” section for how to connect a range of
speakers/subwoofers to the amplifier. To operate Channel A or B in bridge mode,
connect “L” “+” to “R” “-”. The minimum load impedance when bridging is 4 ohm, the minimum load
impedance per channel when using L and R individually, is 2 ohm.
5. Power Connections – This section is labelled “Power” and is where all the power leads are connected to
the amplifier. Particular care must be taken when connecting, NOT to cross/touch any of the cables together.
From left to right, “+” is the positive connection from the battery, “REM” is the remote or ignition connection
and “-” is the negative or earth connection.
– This section is labelled “Input”, and features two pairs of RCA phono sockets, each pair
has one “L” (white - top), and one “R” (red - bottom) RCA socket. These are for the audio input from
the source unit. A source unit that supplies a “line level” (pre amp) audio output in the form of RCA
phono plugs is required to connect to the input (via a phono extension lead). A high quality shielded lead
is recommended as this will help reduce the possibility of noise entering the system.
Also featured on the “Input” is a 2-ch/4-ch switch. Essentially, this saves using splitter leads or adaptors
if only one RCA output is available, allowing one RCA input while utilising the full functionality of the 4-
channel amplifier.
With the 2-ch/4-ch switch off (not pressed in), two pairs of RCA inputs can be used. The input pair
plugged into the input “Channel-A”, will control the speaker(s) connected to the Channel A outputs, while
the input paid into the input “Channel-B”, will control the speaker(s) connected to the Channel B outputs.
With the 2-ch/4-ch switch on (pressed in), one pair of RCA inputs can be used. The input pair plugged
into the input “Channel-A”, will be used for both Channel A and Channel B outputs. This saves having to
use RCA splitting leads/adaptors.
To clarify, here are two examples:
1). The source unit has two RCA outputs, “front” and “rear”. Front is connected to Channel A input, and
rear is connected to Channel B input. A pair of front speakers are connected to the Channel A outputs,
and a subwoofer is connected to Channel B outputs. Settings at the source unit (such as gain, bass
boost, etc ) can be applied to Channel A (“front”) and Channel B (“rear”) independently at the source
unit. The 2-ch/4-ch switch is set to off (not pushed in).
2). The source unit has one RCA output. It is connected to the Channel A input. As in the first example,
a pair of front speakers are connected to the Channel A outputs, and a subwoofer is connected to
Channel B outputs. Settings at the source unit (such as gain, bass boost, etc) can not be applied to
Channel A and Channel B independently at the source unit, because both Channel A and Channel B are
sharing the same input. Any independent changes can be made on the side panel of the amplifier. The
2-ch/4-ch switch is set to on (pushed in).
