Audio Control ACX-300.4 User manual

COMPACT HIGH POWER ALL-WEATHER 4-CHANNEL AMPLIFIER
Quick Start Guide
Features
• Compact High Power 4-Channel Amplier
• High Current Design
• 4 x 50 Watts @ 4 Ohms, 4 x 75 Watts @ 2 Ohms
• 2 x 150 Watts @ 4 Ohms, Bridged Mono
• 12 dB/Octave Linkwitz-Riley Alignment Crossover
• GTO™ Signal Sense (Great Turn On)
• 4 Speaker-level/ Line-Level RCA Inputs
• All-weather IPX6 rated!
• Filled with home-grown audio goodness
ACX-300.4

2
Quick Start Guide
ACX-300.4
Important Safety Instructions
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install in accordance with the
manufacturer’s instructions.
8. Do not install near any heat sources such as muers, silencers, exhaust
pipes, or other apparatus (including ampliers) that produce heat.
9. WARNING: Improper installation may lead to permanent injury or death.
Installation of the apparatus must be done with great care by qualied
personnel, to prevent damage to fuel lines, power and other electrical
wiring, hydraulic brake lines, and other systems, that might compromise
vehicle safety.
10. Provide +12V and Ground wiring of sucient size to ensure adequate
current to the amplier. For the ACX-300.4 this means 8 gauge wire or
thicker.
11. Use rubber grommets to protect wiring whenever passing wires through
metal openings or bulkheads.
12. Only use attachments/accessories specied by the manufacturer.
13. Refer all servicing to qualied service personnel. Servicing is required
when the apparatus has been damaged in any way, such as the power
input terminals are damaged or objects have fallen into the apparatus,
does not operate normally, or has been dropped.
14. Fuses shall be replaced only with the correct type and fuse value, and
only when the apparatus is powered o.
15. Exposure to high sound pressure levels may lead to permanent hearing
loss. Take every precaution to protect your hearing.
The lightning ash with arrowhead symbol within an equilateral triangle
is intended to alert the user to the presence of uninsulated
“dangerous voltage”within the product’s enclosure, that may be
of sucient magnitude to constitute a risk of electric shock to
persons.
The exclamation point within an equilateral triangle is intended to alert the
user of the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the
appliance.
Caution: to reduce the risk of electric shock, do
not disassemble the apparatus, other than to
remove the top panel to access the controls.
There are no user-serviceable parts inside.
Refer servicing to qualied personnel.
Recycling notice: If the time comes and this apparatus has fullled its destiny,
do not throw it out into the trash. It has to be carefully recy-
cled for the good of mankind, by a facility specially equipped
for the safe recycling of electronic apparatii. Please contact
your local or state recycling leaders for assistance in locating a
suitable nearby recycling facility. Or, contact us and we might
be able to repair it for you.

3
1. Speaker Output – Connect these wires to your speakers using
the included water resistant harness. Speaker wire may then be
crimped or soldered onto the bare leads. Use a decent sized wire
gauge as this baby is powerful!
2. Power Input Terminal +12V & Ground – Connect these wires
to the +12V and Negative binding posts of the vehicle battery
via one of two included harness options. You may use either the
included water resistant harness, or the included harness kit to
terminate your own custom-length water-resistant harness. Use
quality insulated wiring of the recommended wire gauge, such as
wire gauge 8 or thicker.
3. Remote Power Input Wire – This wire connects to the 12V
remote trigger output of some head units and controls the on/o
state of the amplier. Alternatively, you can use the GTO™ feature
of the amplier so it will turn on when an speaker level signal is
detected at the RCA inputs.
4. Power LED - When the unit has been powered on, the LED will
glow warmly red.
5. Input Level - Use this switch to specify which type of signal input
voltage type you are using - high is speaker level & low is the RCA
line level
Connection Panel Features
1 2 3 4 5 6 7 8 9 10 1112 13

4
Quick Start Guide
ACX-300.4
6. Protection LED - This LED will shine if there is a problem being
sensed by the unit. See troubleshooting section for best practice
to determine the cause.
7. Gain Control 1/2 - This control allows you to adjust the overall
output level for channels 1/2, with counterclockwise decreasing
and clockwise increasing. With the source unit set to 75%, adjust
this knob to the point where the Maximized light shines briey.
This will be your optimal gain setting.
In Stereo operation, connect one loudspeaker to each channel as
shown. The minimum impedance is 2 Ohms per channel.
In Bridged Mono operation, connect one loudspeaker to the
inner 2 wire connections labeled 1 and 4 on the included mating
speaker wire connector. The mono loudspeaker will receive the
power from each channel, and both channel inputs must be fed
an input signal. The minimum impedance is 4 Ohms.
8. High Pass Crossover Frequency 1/2 – Since component speakers
are designed to reproduce certain frequency ranges, a crossover
allows you to match the speaker to the appropriate frequency
range. Speaker manufacturers list a recommended crossover
frequency in the speaker specications so choosing the crossover
point they’ve noted will provide increased speaker reliability and
optimum sound quality. The ACX-4.300 amplier has selectable
12 dB/Octave Linkwitz-Riley crossover points at 80 Hz, 120 Hz,
and a “bypass” option. The amplier receives the frequency range
above the crossover point.
4 5 6 7 8 9 10 11 12 13 14

5
Control Panel Features
9. Input mode - If you have both front and rear input signals avail-
able - either by speaker level or line level - set this adjustment to 4
Ch mode. If you only have 2 signal wires, then set this to 2 Ch and
the signal received on inputs 1/2 will be distributed out to 1/2 and
3/4 amplier outputs.
10. Gain Control 3/4 – Similar to the gain control for channels 1/2,
this control allows you to adjust the overall output level for
channels 3/4, with counterclockwise decreasing and clockwise
increasing. With the source unit set to 75%, adjust this knob to the
point where the Maximized light shines briey. This will be your
optimal gain.
11. High Pass Crossover Frequency 3/4 – Similar to the High Pass
Crossover control for channels 1//2, this setting controls the High
Pass Crossover for channels 3/4. Set this according to your speaker
manufacturers recommended setting found usually on the back
page of the their documentation or manual.
12. Maximized – This LED will shine when the signal is approaching
the clipping point. Please note that there are 2 of these LEDS - one
for channels 1/2 and the other for channels 3/4. With your source
unit turned up most of the way, use your gain controls to dial in
the output by watching for this LED to shine, then back it o just
a touch.
13. GTO™ signal sense – In the ON position, the ACX-300.4 amplier
will gracefully turn on when it detects an incoming audio signal
and turn o after a period of time when the audio signal fades
away to silence. In some situation, factory installed audio systems
may turn on or “wake up” due to convenience features like door
chimes, alarms or cell phone signals that trigger the source unit
in the vehicle to come on. To prevent these from turning your
audio system on unexpectedly, you can bypass the GTO™ circuit
by moving the switch to the OFF position and use a switched 12v
trigger from the vehicle.
14. RCA inputs - Connect your source unit’s signal output wires to
these RCA inputs. If you only have 2 then set Input Mode to 2 ch,
if you have 4 set Input Mode to 4 Ch. When connecting a speaker
level signal to these inputs, ensure that the Input Level setting is
set to High.

6
Quick Start
Here are a few general steps to get your ACX-300.4 amplier up and
running:
1. Undo the +12V and Ground connections to the vehicle battery
before making any connections to the amplier.
2. Pick a mounting location that will provide access to the controls
and connections, provide plenty of good ventilation.
3. The ACX-300.4 amplier needs to be securely mounted using the
four mounting holes located in each corner.
4. Before drilling any holes, take every precaution to prevent
any damage to fuel lines, power and other electrical wiring,
hydraulic brake lines, and other systems, that might compromise
vehicle safety.
5. When making connections, designate red RCA plugs as right,
and designate white, black, or gray plugs as left. This is a good
idea for consistency.
6. Use quality interconnect cables.
7. Connect the +12V input wire on the included wiring harness
assembly to the +12V terminal of the vehicle battery, using the
appropriate gauge wire.
8. Connect the Ground wire of the power wiring harness assembly
to a ground source such as the negative battery terminal, vehicle
chassis or other ground source, using the same wire gauge as
the +12V power wire.
9. Connect the remote power terminal of the unit to the remote
turn-on switch of your source unit. Alternatively, you can skip
this connection and use the GTO™ Signal sensing.
10. Connect your audio inputs to the unit – either speaker-level or
line-level RCA… not both.
11. Connect your loudspeakers (minimum impedance of 2 Ohms
stereo, or 4 Ohms bridged mono).
12. When all connections are made, reconnect the vehicle battery.
13. Adjust your gain settings to maximize your signal level.
14. Set the ACX-300.4 crossovers to the frequency recommended by
the loudspeaker manufacturer.
15. Enjoy the drive!

7
Quick Start Guide
ACX-300.4
Power Connections
In this example, the head unit has a +12V trigger
output that is connected to the ACX-300.4 remote
input terminal. When the head unit is turned on, it
will turn on the ACX-300.4 amplier.
Alternatively, the GTO™ signal sense feature can
be used to gently turn on the ACX-300.4 amplier
when an audio input signal is detected. (The con-
nection to the ACX-300.4 remote input terminal is
not required when using the GTO™ signal sense.)
Source Unit
GND
+12V
To battery
12V Trigger
Speaker-level outputs
REM
GND
+12V

8
System #1: Using Speaker-Level Inputs
+
+
INPUT 2
INPUT 3
INPUT 4
INPUT 1
O
U
T
P
U
T
1
O
U
T
P
U
T
4
O
U
T
P
U
T
3
O
U
T
P
U
T
2
Speaker level output
80Hz and down
Speaker level outputs
80Hz and up
Source
unit
Signal Wires
OUTPUT
INPUT 1
INPUT 2

9
Cover Plate Removal
The cover plate must be removed to gain access to
the controls, and then sealed again to protect the
controls against moisture and debris.
Removal Procedure
1. Locate the top six hex screws that hold down
the sealed top cover.
2. Use a 2.5mm hex wrench to remove the six
screws.
3. Gently lift cover o. It’s a very tight t there, so
you may need to use some gentle force. Yes, it is
with you!
4. Keep the cover plate and screws in a safe and
handy place, until you have nished adjusting
the controls to your immense satisfaction.
REM
GND
+12V

ACX-300.4
Quick Start Guide PN 914-023-0 Rev A
Specications
All specications are measured at 14.4 VDC (standard automotive voltage). As technology advances, AudioControl reserves the right to continuously
change our specications, like our Pacic Northwest weather, although we are working on changing that as well.
The ACX-300.4 Amplier
Power Output (RMS) ...........................4x50 Watts @ 4 Ohms
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4x75 Watts @ 2 Ohms
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2x150 Watts @ 4 Ohms Bridged
Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Hz - 30 kHz
Total Harmonic Distortion + N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . < 0.05%
S/N Ratio ........................... 102 dBa, Ref 50 Watts @ 4 Ohms
Power / Ground Wire Gauge ...................Between 8 and 4 AWG
Crossover. . . . . . . . . .12dB/Octave Linkwitz-Riley, 80 Hz, 120 Hz, Bypass
Line/Speaker-Level Inputs . . . . . . . . . . . . . . . . . . 500mV - 6V/1V - 12VRMS
Weight .......................................................2.1 lbs
Dimensions...............................9.41"W X 2.97"D X 1.75"H
©2020 AudioControl. All rights reserved.
AudioControl
22410 70th Avenue West, Mountlake Terrace, WA 98043 USA,
Phone [phone], FAX [phone]
email: [e-mail]
Warranty
For details of the limited warranty for your ACX-300.4, please visit the
following page on our website: audiocontrol.com/warranty
Please keep your receipt in a safe place.