6. Low Pass Filter (LPF) control
– This knob controls the highest frequency range that is sent to the
subwoofer(s). The range is adjustable, from 40 to 180 Hz with a third order slope of 18 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.
7. Subsonic Filter
– The subsonic filter is the opposite of the LPF; the knob controls the lowest
frequency range that is sent to the subwoofer(s) (effectively a high pass filter). When the knob is turned
fully anti-clockwise, the filter is off. To switch the subsonic filter on, simply turn this knob clockwise,
from which point, the range is adjustable from 5 to 50 Hz with a third order slope of 18 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 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 subsonic filter. For some tastes and situations, the subsonic filter
may not need to be switched on at all.
When set correctly, the subwoofer is able to work more efficiently, and the lower frequency range
reproduced is configured to the equipment, surroundings and user taste.
8. Bass Boost Frequency
– This knob controls the frequency at which the gain or volume of bass can
be enhanced/boosted. The frequency selectable with this knob is the mid-point of the boost; frequencies
slightly above and slightly below this point will also be boosted. The gain or amount of bass boost
applied at this frequency is set with knob 9 (bass boost – described below). The range of frequencies
that can be boosted is 30 Hz to 80 Hz.
9. Bass Boost
– This knob controls a boost of the bass frequencies at the desired frequency set with
knob 8 (bass boost frequency). The amount of bass boost that can be applied is 0 – 12 dB. There is no
“bass boost” (bass boost is off) when the knob is turned fully anti-clockwise. Turning the knob clockwise
from this position gradually boosts the frequencies around the desired region. Bass boost can often
result in an uneven and unnatural bass frequency response, which may be desirable or not desirable
depending on user taste and the type/genre of audio being reproduced. Bass boost can be used to help
even out an uneven frequency response.
10. Speaker Connections
- These are screw terminals for attaching the subwoofer speaker cables.
Undo the screw head enough to slot a stripped end of subwoofer speaker cable into the terminal, and
then tighten the screw. Please see wiring diagrams in the “Installation” section for how to connect
subwoofer speakers to the amplifier.
11. Power Connections
– This is where all the power leads are connected to the amplifier. Particular
care must be taken when connecting, NOT to cross any of the cables.
“+12v” is the positive connection from the battery. “- GND” is the negative, ground or earth connection
and “REM” is the remote or ignition connection.
Mounting Instructions
Before mounting, please read the “Installation” section. The best place to mount the amplifier is
somewhere where it will not get damaged, eg. by items in the boot of the vehicle. The amplifier
dissipates heat using its heat sink; somewhere with sufficient space and air would be fine. Therefore
placing the amplifier in between items, placing items on top of it, or mounting it upside down is not
advisable. This amplifier must be installed horizontally (flat) with plenty of air around it, or the amplifier
may be in serious risk of damage. Examples of surfaces to mount on are the floor of the boot or fake
floor of boot (MDF). Never mount the amplifier on its side. Never mount the amplifier onto a subwoofer
box as this can damage the amplifier. Never mount the amplifier outside of the car, in the engine bay or
anywhere where it has a risk of getting wet. Normally it is best to attach the amplifier to a board, and
then attach the board to the car body. This is good practice to avoid noise problems.
Before mounting, make sure that the surface is suitable and free from any obstructions. Use the
amplifier as a template and mark where the holes are to be drilled with a pencil or pen. Drill the pilot
holes with a drill bit of diameter smaller than that of the screws. Then place the amplifier on the surface
and tighten the screws until they are holding the amplifier securely in place.
OWNER’S MANUAL
Control Panel Functions
1. 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 has shut down to protect
itself from permanent damage. This will be due to one of the following: excessive heat, reverse polarity,
short circuit or input overload. If this happens disconnect the amplifier and investigate the problem.
2. Remote Gain
– The supplied “Remote Gain Controller” plugs into this socket. With a long run of
cable attached, the gain controller can be positioned in the front of the car so that the level of the output
can be adjusted from the front. Most source units support “fade” function, where the level of the pre-out
signal sent to the amplifier from the source unit can be altered giving exactly the same effect. However,
this provides a hard-wired solution to gain control from the position of the listener. Please see “Gain
Control” notes below. Connection is optional.
3. Audio Input
– This section is labelled “Input”, and consists of two RCA phono sockets, one “R” (red)
and one “L” (white), above each other. These are for the audio input. 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.
4. Bridge In/Out
– This section consists of two RCA phono sockets, and is only to be used if two of the
TL-1023 amplifiers are used together, sometimes called “strapping” or “bridging”. This can be done very
simply and easily and is explained in detail later on in this manual.
5. Gain Control
- Turning the 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.
The control panels for the TL-1023 are as follows:
OWNER’S MANUAL
Side 1:
Side 2:
