How to install and
operate the
DLS CAT31
24 V amplifier
Welcome!
This owners manual is written in easy english and
uses a lot of drawings to simply the installation and
use of the above amplifier.
Your DLS amplifier must be installed correctly in order to work well. This manual will show you how to
install the amplifier like a pro. Please read the entire
manual before beginning the installation.
Install the amplifier yourself if you feel confident with
our instructions and if you have the proper tools.
However if you feel unsure, turn over the installation
job to someone better suited to it.
Warranty Service
This amplifier is covered by warranty, depending on
the conditions in the country where it is sold. If the
amplifier is returned for service, please include the
original dated receipt with the product.
Technical Assistance
Contents
Specifications.............................. 1
Features…………………………….. 2
Installation…………………….……. 2
Trouble shooting…………………… 2
Tools and materials needed………. 3
Amplifier installation kit………….... 3
Routing Wires…………………….... 3
Wiring
Power and Outputs……………..…. 4
Inputs and controls………………... 5
Input level control.......................... 5
Crossovers…………...................... 5-6
Phase control.....………………...… 5
Speaker wiring:
Front stereo speakers................... 6
Subwoofers.................................. 6
Test............................................. 6
Connecting a center channel speaker 7-8
Professional tips…………...…….... 9
For technical assistance ask the shop where the product
was sold or the distributor in your very country.
You can always phone the DLS Helpdesk in Sweden
+ 46 31 84 00 60 or send an e-mail to info@dls.se.
Information can also be found on our WEB-site
www.dls.se
DLS Svenska AB - 2007-01-10
Approval of electromagnetic compatability according
to the EEC Directive 95/54/EC
CAT31 -24 Volts - features
RCA stereo channels input
High level input with auto start
Mono channel: RCA input or input from stereo
channels
Continuous variable low pass crossover
Continuous variable high pass crossover
Subsonic filter 25 Hz fixed ON-OFF
Phase control cont. variable 0-180 degrees
Electronic protection circuitry against
short-circuit, DC offset and thermal overload.
Installation
Before you begin the install
Before you begin you need to read the manual, to have
some tools, cables and other material available. There
is one such list of material on the following page.
CAT31
Trouble shooting
If problems occur during the installation, or later,
this guide might help you to find out whats´s wrong.
The amplifier is dead:
1. Check power lead, ground and connections at
the amplifier using a multi meter.
2. Check the battery terminal connections.
3. Check the power lead fuse or circuit breaker. If
fuse damage continues, inspect the power lead
for short circuits.
4. Check the amplifier protection fuses. Are these
broken change to new ones with the same value.
If short circuiting continues, contact your local
DLS dealer. A fault may exist in the amplifier.
5. To start the amplifier requires a remote voltage
of 12-30 volt. Check the voltage with a multi
meter.
Amplifier location
Important
Allow air circulation around the amplifier.
The DLS Classic series of amplifiers have a
compact design that allows great flexibility in
mounting. You can mount it under a seat or in the
trunk.
When you select a location, do remember that the
amplifier generates a lot of heat.
Choose a location where air can circulate freely
around the amplifier. Do not cover the amplifier with
carpets or hide behind trim panels.
Do not mount the amplifier in an inverted or upside
down position.
Check all locations and placements carefully before
making any cuts, drilling any holes or making any
connections.
This is the best direction to
mount the amplifier to get
the best cooling.
Removal of side flanges
Amplifier protection fuse blows at low
volume:
One or more speaker cables are shorted. Make an
insulation test with a multi meter. The cables must
not have a connection to earth.
The amplifier turns off after 10-30 minutes:
The amplifier is overheating due to inadequate ventilation. Check mounting position is free from
obstruction.
Do this:
1. Move the amplifier to a place with better ventil-
ation.
2. Install one or two fans to cool down the heat sink.
3. Overheating can also be caused by an
impedance load below the level permitted.
No output from the speakers:
Check the following:
1. Speaker cable connections to both amplifier and
subwoofers.
2. Signal lead plugs and cables.
DLS logo on amplifier cooling flange
In order to fasten the amplifier to the surface and
connect speaker and power cables, the flanges on
the sides must be removed. This is done by
loosening the hex screws on top of the amplifier.
Use a 3 mm hex key.
Remove these
screws using a 3
mm hex. key for
removal of side
flange. Remount
after fastening the
amplifier and
connection of the
speaker and power
cables.
2
The DLS logo on top of the amplifier is attached
with two hex. screws. The logo can be removed
and twisted 90 or 180 degrees, and then screwed
back in wanted position. The logo can be mounted
in four different ways to match your installation.
Disconnect Battery
Before starting the installation, always disconnect
the negative terminal of
the battery.
CAT31
Tools and material needed
Tools:
Flat and Phillips screwdrivers
Wire cutter
Wire stripper
Electric drill with drills
Crimping tool
Digital multimeter or test lamp
Wire brush, scraper or a piece
of an abrasive sheet to remove
paint for a good ground connection
Grease to protect the ground
connection from corrosion
Material:
Speaker wire: minimum
12 AWG = 4 mm2 for subwoofers
Sheet metal screws for mounting the
amplifier to the amplifier board and the
amplifier board to the car + some extra
for fuse holder, amplifier ground etc.
Electrical insulation tape
½ inch thick plywood or particle board for
the amplifier to be mounted upon.
Routing wires
Stereo
head unit
Amplifier installation kit:
If available,buy an amplifier installation kit. It
contains normally all you need. This is what you
have to buy if you buy the items separately.
Power cable, AWG 7 = 10 mm2 or heavier
1 pc of fuseholder to install close to the
car battery + fuse 40 Ampere.
20 feet of AWG 15 = 1,5 mm2 wire for
remote turn on / off cable from radio.
RCA-cable for input from radio.
- 20 feet or 5 meter for trunk installations
-12 feet or 2 – 3 meter for under seat
installations
One min. 8 gauge ring crimp terminal
for the amplifier ground connection.
Wire ties
Insulating grommet or insulating tube
High current draw
The CAT31-24 Volt is an amplifier with high power output. The current draw is also high so you must make
sure that your vehicles power system (battery and
alternator) can provide all the power you need. If you
have a bad battery or alternator in can result in a poor
sound or even worse, a broken battery or alternator.
Professional Tip:
If amplifier installation kits are available with different size of power cable, chose the most heavy
power cable to improve sound quality and to allow
more amplifiers to be installed now or later.
If possible buy AWG 5 = PL 16 mm2 (or heavier)
cable for best performance.
3
Remote terminal ( REM )
CAT31
Wiring
Power and Outputs
Power terminal ( +24V)
Connect the fuse holder as close to the vehicle
battery + as possible, using AWG7 = 10 mm2 or
heavier cable. Use ring crimp terminal cable to
connect to battery +. Apply silicon grease to the
fuse to prevent corrosion.
The fuse value depends on the
size of the power cable.
A 16 mm2 cable can have a
60A fuse.
DLS
DLS FH 1B
fuse holder
Connect the battery cable to the +24 Volt terminal
on the amplifier.
Be sure to use a rubber grommet or a plastic
insulating tube where the cable passes the firewall
or other places when it can easily be jammed.
Use wire ties to secure to existing cables in the engine
room. If you buy another power cable than the
recommended, use the follwing maximum fuse
values.
Max. fuse value for different cable sizes:
2
6 mm
(9 AWG) :25 A 10 mm2 (7AWG) :40 A
16 mm2 (5AWG) :60 A 21 mm2 (4AWG) :100 A
2
33 mm
(2AWG) :150 A 42 mm2 (1AWG) :200 A
+24V REM GND
+12V REM GND
For RCA cable signal input:
Connect the radio power antenna lead = remote turn
on/off from the car stereo to the amplifier remote
connection. This turns on the amplifier whenever
the car stereo is turned on.
You can either use the built in remote cable in the
RCA cable itself or use a separate cable.
Sometimes a small disturbance may enter the
amplifier coming from the remote voltage , through
the built in remote wire and into the RCA cable. Thus
we recommend to use a separate remote wire and
run the RCA lead separate from remote wire, power
cables and speaker cables.
You can either use a crimp fork terminal or insert
the cable directly into the amplifier terminal. If there
is no remote voltage available from the stereo, you
must connect to the ignition key through the radio
or any accessories fuse.
For High Level input:
We recommend you to connect the remote wire as
described above.
The amplifier will be turned on/ turned off by the
high level input voltage. This is done when the Hi
level/Low level switch is set to Hi level position.
There is a small disadvantage that this function
gives soft turn on operation but some plop sound
when switching off.
You do not have to connect any remote voltage
when using Hi level input.
+12V REM GND
+24V REM GND
Ground Terminal ( GND )
Connect to a good chassis ground. The ground
connection should be clean, unpainted metal to provide a good electrical connection. Use a wire brush, a
scraper or a piece of an abrasive sheet to clean the
metal. Use a lock washer or two to secure contact.
Protect with silicon grease or by paint applied
afterwards.
+12V REM GND
+24V REM GND
4
Power Light / Protect light
The power light (green ) comes on when
the amplifier is turned on.
The protect light ( red ) comes on when
the amplifier shuts down from
overheating or short circuit.
Fuses
Use only 20 ampere ATC blade
type fuses. CAT31 uses two 20
ampere fuses.
Power
(Green)
Protect
(Red)
20A
Input and controls
CAT31
Input Wiring
Inputs may be low level from the RCA output of the car
stereo or high level from the car stereo speaker
output.Low level = RCA is to prefer for the best sound
quality.
Important
Use either the low level or the high level input, do
not use both at same time.
Low level input
Use a pair of shielded stereo audio cables with RCA
type jack. The cable length varies depending on type
of vehicle. Most cables can be
bought in lengths from 1 up
to 5,5 meters.
Avoid placing the RCA cable
close to speaker cables,
power cables and remote
control cable. Connect to input socket A & B.
High Level Input
Connect left and right speaker wires coming from
the car stereo to the high level input as shown. You
must connect both plus and minus as the inputs are
balanced, connecting plus only gives lower level and
bad sound quality. By changing the polarity of plus
and minus, you can change the phase.
High Input
Hihg level input socket.
Automatic turn on when using high level input.
With the Hi/Low input swich set to Hi, the amplifier turns
on automatically on high input. You don´t need to connect
a separate remote wire from your head unit.
When using High Level input:
Set the switch to position ”Hi / Level”
When using Low level input:
Set the switch to position ”Low / Level”
If the switch is set to wrong
position, the amplifier still
works, but the risk for
disturbances or distortion
increases.
White :A ch.+
White/black :A ch.Grey/black :B ch.Grey :B ch.+
Hi / Level
Low / Level
Input Level control ch. A/B/C (Level)
The input level control, 5V – 0,25 V,
matches the output of your radio to the
input of the amplifier. After installation
is complete, make sure the input of the
amplifier is turned down all the way
( counter-clockwise at 5V ). Play a tape
or CD, make sure all bass or treble
Level
settings or equalizer are flat, and turn
the volume of the radio up until you
just start to hear distortion. Turn the
5 V 0,25 V
volume control down just a bit. On the
amplifier increase the input level control
( clockwise or to the right ) until you just
start to hear distortion, then back the
level control just a bit. Now your radio
and amplifier levels are matched.
Subsonic filter ch. C
The Subsonic filter blocks the very
deepest frequencies from reaching the
subwoofers. The filter crossover is 25
Hz and can be disconnected.
Subsonic
Off On
Low pass filter ch. C (LPF)
The LPF ( low pass filter ) allow low
frequencies only and blocks higher
frequencies. A typical setting is 60 – 80
Hz. Choose the setting that sounds best
in your car.
LPF
50Hz 120Hz
Phase control ch. C (PHASE)
The phase control can be set
continuously from 0 - 180 degrees. This
is very useful when you want to adjust
the bass sound for best front stage image.
Start on 0 and turn the control slowly
clockwise until you experience the bass
sound coming from the front.
You may have to change the polarity of
the speaker connection to get the best
result.
Phase
0o180
o
5
+ 24V
CAT31
Parallel input
Parallel
Input
Off PC
In position PC the signal is internally
connected from input A/B to the input
for channel C. A single RCA cable is
enough to feed all channels. In OFFposition you must use dual signal
cables or Y-splits.
High pass filter ch. A/B (HPF)
With the HPF-filter in OFF posi-
HPF
50Hz 220Hz
15Hz
Off On
Filter settings ch. A/B
With the HPF-filter in OFF position the amplifier
allows the speakers to play fullrange. If you for some
reason want to limit the low bass reproduction switch
on the HPF-filter. The typical setting is then around
60 – 80 Hz.
Filter settings ch. C
tion the amplifier allows the
speakers to play fullrange.
If you for some reason want to
limit the low bass reproduction
500Hz
switch on the HPF-filter. The
typical setting is then around 60
– 80 Hz.
Connection of front speakers
Two fullrange speakers
connected to ch. A / B.
CAT 31 can handle speaker loads down to 1 ohm
per channel. You can
connect four 4 ohm
speakers in parallel on
each channel.
Connection of subwoofers
One or two
subwoofers to
the sub channel
(C).
You can connect
two 4 ohm subwoofers on the
sub channel
without any risk
for overload.
+ + C CH - -
The subsonic filter takes away the very deepest
frequencies. Turn on the subsonic filter if you want
to remove these frequencis.
The LPF will allow low frequencies only and blocks
higher frequencies. A typical setting is 70 – 100 Hz.
The phase control can be set continuously from 0 180 degrees. This is very useful when you want to
adjust the bass sound for best front stage image.
Start on 0 and turn the control slowly clockwise until
you experience the bass sound coming from the
front. If you dont get the result you want, also try to
phase reverse the subwoofer connections and make
a new adjustment.
Testing
Before you finish the installation, you should do the
following tests to make sure the wiring is correct
and everything is operating properly.
Reconnect Battery
When wiring is complete,
reconnect the battery
negative terminal.
Test power wiring
1. Turn on the head unit but do not turn up the
volume. The amplifier power light should
come on. If not, check the remote and +24
volt wires. Also check the ground
connection.
2. Turn up the head units volume slightly. All
speakers should operate. if not, check
wiring connections at amplifier and
speakers.
6
Truck installations / Center channel
1234
1234
12
12
12
12
1234
1234
speakers
The main differences between a sedan car for personal use and a truck are:
- 1 the wideness of the car and
- 2 the high noise level in a truck in motion.
This makes it hard for the driver to listen to the right
speaker ( if the steering wheel is on the left ) and for the
passenger to hear the speaker on the drivers side.
You can also use one speaker only, but connect it to
the CAT31 amplifier in the bridge mode way. Thus the
speaker will receive the Left + Right channel.
As this voltage is twice as high as what we feed to the
left or the right speaker, we now must use a voltage
divider or attenuator to bring down the power to what is
suitable for the speaker.
Although a single driver can adjust the balance left right
to compensate for this, a better solution is to add a
center channel speaker / speakers.
Often you use a 4 or preferably a 5.25 inch speaker
positioned at the center of the dashboard. Very often
you use two speakers of reasons we will show later.
One center speaker connects to the left channel, but
often at a lower level compared to the main speaker.
The other center speaker connects likewise to the right
channel. The two speakers together will thus play the
sound of Left + Right.
This will fill in what you can call the gap in the
soundstage of the earlier installation.
Your side system will hopefully be good 6,5 inch coaxes
or two-way systems or even better. A small center
channel speaker of smaller size will have to be feed at
a lower level of volume and if possible through a band
pass filter to limit the frequency response to say 500 6000 Hz.
Connecting two center channel speakers
with bandpass filter
The drawing below show how to connect two center
channel speakers to the CAT 31, through a voltage
dividing circuit. Using a potentiometer you can adjust
the volume from the speaker.
If you want to connect a bandpass filter, do so by
using the filter design suggested on next page.
Connecting one center channel speaker
in bridge mode with bandpass filter
The drawing below show how to connect one center
channel speakers to the CAT 31, through a voltage
dividing circuit. Using a potentiometer you can adjust
the volume from the speaker.
If you want to connect a bandpass filter, do so by
using the filter design suggested on next page.
+ A-CH - - B-CH +
Left
Front speaker
+
-
R = 50 ohm
15 Watt
0-20 Ω
15 Watt
+
-
Center channel
Left + right
Front speaker
Bandpass filter
Right
+
-
+ A-CH - - B-CH +
Left
Front speaker
+
-
R = 20 ohm
15 Watt
0-20 Ω
15 Watt
+
-
Left
Center channel
Bandpass filter
Front speaker
R = 20 ohm
15 Watt
0-20 Ω
15 Watt
+
-
Center channel
+
-
Right
Right
It is not necessary to use a bandpass filter, only if you
want to limit the frequency range. The bandpass filter
limits the frequency range from 500 to 6000 Hz.
On next page is a drawing if you want to build your own
bandpass filter.
7
3
3
3
3
6
Center channel from car stereo head unit
If you don´t have any attenuators or bandpass filters
available, there is a simple connection using the built
in power of a 2 x 20 Watt or 4 x 20 Watt head unit.
Although most headunits are refered to as 2 x 35 Watts
or more, the true RMS power is normally 2 x 14 Watt in
a four ohm load. The reason you buy an amplifier is to
raise the available power to 2 x 75 Watt, roughly 5 times
more. However as a sort of fill in the built in power can
serve, as long as you do not push the car stereo into
distortion.
The center channel speakers can be connected to say
rear left and to rear right.
Using your fader control between front and rear you
can adjust the volume of the center speakers in
comparison to the main speakers feed from the amplifier
The center channel speakers will produce 2 x 15 Watts.
Should you have one center speaker only, you can even
connect it as above, but to rear left plus and to rear
right minus. This way the speaker will reproduce Left +
Right channel but only with 1 x 15 Watt.
Bandpass filter for 500 Hz - 6000 Hz
for a 4 ohm speaker
50 μF
1,75 mH
core coil
2
2
2
2
+
-
0,15 mH air coil
2345
+
4,7 μF
-
For 2 ohm speakers (two 4 ohm in parallell) or an 8
ohm combination (two 4 ohm in series) chose the
values in this table.
Spkr imp. L1 C1 L2 C2
2 ohm 0,07 mH 10 μF 0,9 mH 100 μF
4 ohm 0,15 mH 4,7 μF 1,75 mH 50 μF
8 ohm 0,3 mH 2,2 μF 3,5 mH 25 μF
You can of course use two bandpass filters and
connect one filter between the amplifier and each
speaker.
Connecting one center channel speaker
in bridge mode to rear output of car
stereo head unit.
Car Stereo
FRONT REAR
L R L R
+ - + - + - + -
-
+
RCA leads to
CAT 31 amplifier
From L+ and R1 x 15 Watt
center channel
fill in left + right
Connecting two center channel speakers
to rear output of the car stereo head unit
Car Stereo
FRONT REAR
L R L R
RCA leads to
CAT 31 amplifier
+ - + - + - + -
+
-
2 x 15 Watt
center channel
fill in
Observe
polarity
-
+
8
CAT31
Professional Tip:Professional Tip:
NOISE PROBLEMS
WHINING NOISE VARYING WITH ENGINE
REVOLUTIONS:
Do this:
1. Rewire the power supply (24 V) to source
unit direct from battery.
2. Rewire ground wire from source unit to
clean position on chassis.
3. Check all power connections to ensure that
they are clean and tight.
4. Check quality of system ground connection.
5. Install a Power Cap capacitor. This can be
helpful against most noise problems.
CONSTANT WHINING NOISE:
Do this:
1. Ensure that all equipment has a common
ground point.
2. Check quality of earth strap connection from
battery negative terminal to chassis.
3. Disconnect signal cables from amplifier to
see if noise disappears. If so the leads are
picking up noise. Test this by laying a new
cable over the seats and reconnecting to the
amplifier. If the noise does not return, reroute original cable away from source of
interference.
If noise remains regardless of cable position,
try to use so called Quasi-balanced signal
cables. DLS PRO or ULTIMATE cables are
quasibalanced.
SPEAKER POLARITY CHECK.
All speakers in a car audio system should be
connected in phase (the same polarity). All speaker
cones must move in the same direction. Out of
phase speakers will cause a lack of bass, and a
poor stereo soundstage.
Checking polarity:
Hold the - connection of the speaker wire to the terminal of a 1,5 Volt flashlight battery. Tap the +
wire on to the + terminal of the battery, and observe
the movement of the cone. The cone should move
outwards when the wire touches the battery, and
inwards when the battery is removed. If it is the
other way around, the speaker has been connected
backwards and it must be removed and connected
correctly.
If your system also has a subwoofer connected
through a passive 6 or 12 dB crossover, try to
connect this with various polarity and judge what
sounds best. The phase shift in passive crossovers
sometimes makes it necessary to change polarity.
+
Batteri
1,5 Volt
+
-
-
Professional Tip: Professional Tip:
Installing in trunk
When installing the amplifier in the trunk, run the
power wires along the same path as the other vehicle
wiring. Many cars have insulated channels for wiring.
you will have to remove the door sill trim and the
carpet.
Securing wires
Use wire ties to bundle together when possible.
(But never bundle speaker wires or signal cables
together with power wires.
Professional Tip:
Crimp connections
Purchase crimp connectors and crimping tool.
Connectors are color coded.
1. Strip 1/4 inch (6 mm) of insulation from the wire.
2. Insert into connector
3. Crimp tightly
Professional Tip:
Speaker and power wires
Do not run speaker and power wires next to each
other. Power wires can generate a ”siren” sound in
the speakers. Runs speaker and power wires on
opposite sides of the vehicle.
9
Specifications
DLS Performance CAT31 - 24 Volt
Number of channels 3
Stereo Channels: Ch A & B
RMS power out in 4 ohm ( 0,1% THD) 2 x 75 Watt
RMS power out in 2 ohm ( 0,1% THD) 2 x 145 Watt
RMS power out in 1 ohm ( 0,5% THD) 2 x 210 Watt
RMS power out in 4 ohm bridged mode 1 x 280 Watt
Filters high pass 50 – 150 Hz
Mono Channel: Ch C
RMS power out in 4 ohm 1 x 170 Watt
RMS power out in 2 ohm 1 x 280 Watt
Filter subsonic 24 dB slope 25 Hz fixed*
* can be switched in or out
Filter low pass 24dB slope 50 – 120 Hz
Phase control mono channel continuous var. 0 – 180 degrees
All above output power ratings at 28V DC
Input impedance, low level (RCA ) > 10 kohm
Input impedance, high level 100 ohm
Input sensitivity, low level ( RCA ) 0,25 – 5 V
Frequency range 10 Hz – 35kHz
Signal to noise ratio, A-weighted > 90 dB
Power consumption, idle / max 0,7 A / 40 A
Fuses 2 x 20 A
Dimensions, mm 70 x 400 x 268
Dimensions, inches 2,92 x 15,75 x 10,55
Weight 4,8 kg / 10,58 lb
DC voltage range 24 – 30 V DC
Remote voltage range 12 – 30 V DC
We follow a policy of continuous
advancement in development.
For this reason all or part of
specifications & designs may be
changed without prior notice.
10
DLS Svenska AB
P.O Box 13029
SE-40251 Göteborg
Tel: +46 31 840060
Fax: +46 31 844021
E-mail: info@dls.se
www.dls.se
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