Infinity BassLink II User Manual

BassLink II

Powered Automotive Subwoofer

SERVICE MANUAL

Infinity Systems, Inc.

250 Crossways Park Dr.

Woodbury, New York 11797 Rev0 8/2005

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Powered Subwoofer Basslink II

- CONTENTS -

SPECIFICATIONS ………………………………….……..1

PACKAGING…..………………………………….………..2

CONNECTIONS/APPLICATIONS………………………..3

CONTROLS AND FUNCTIONS.……...……..…...…...…6

BASIC TROUBLESHOOTING..…….…….………………8

DISASSEMBLY PROCEDURE.……...….…..…...…...…9

EXPLODED VIEW…………………………………..……10

AMPLIFIER BLOCK DIAGRAM…………………………11

ELECTRICAL PARTS LIST ……………………………. 12

P.C.B. DRAWINGS….…………………………………….18

IC/TRANSISTOR PINOUTS…………………………….. 30

SCHEMATICS.................................................................31

Basslink II Specifications

Output Power (14.4V supply) 250W RMS 1% THD
Type of Amplifier AB
Frequency response: 20Hz – 120Hz
Maximum input signal: 4.0V
Maximum sensitivity: 50mV to 4V Line-level input

1V to 16V High-level input

Input Impedance 20K Ω
Idle Current <800mA
Signal to Noise >100dB (A-weighted ref to full power)
Crossover Type Fixed LP @ 12dB per octave
Crossover Range Variable 50 – 120 Hz
Bass EQ 40Hz (-6dB to +3dB)
Phase Control 0 and 180°
Min Current Draw (Idle) <800mA
Remote Current Draw <3.5mA
Max Current Draw 26A
DC Offset <30mV
Bass Boost -6dB to +3dB @ 40Hz
Auto Turn-On 2 -10min (Time to turn Off)
Operating Voltage 10 – 16 VDC

Overall Dimensions (L x W x H): 15-1/16" x 8-3/4" x 15-5/16"

(383mm x 223mm x 389mm)
Sub Level Control (w/ housing): 2-3/16" x 2-5/16" x 7/8"
(56mm x 59mm x 23mm)
Sub Level Control (w/o housing): 2-3/16" x 1-5/16" x 3/4"
(56mm x 34mm x 20mm)

Fuse: 25A

Infinity continually strives to update and improve existing products, as well as create new ones. The specifications and details in
this and related JBL publications are therefore subject to change without notice.

Powered Subwoofer Basslink II

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Powered Subwoofer Basslink II

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POWER CONNECTIONS

Make Power, Ground and Remote turn-on
connections as shown in Figure 5. Observe
the following installation tips:

• Use #8 AWG wire for the +BATT (+12Vdc)
and GND (ground) connections. If needed, use
at least a #20 AWG wire for the REM (remote)
connection.

• If you pass the power or remote wire
through the vehicle’s firewall or other metal
obstruction, it must be insulated with a rubber
grommet. If a factory-installed grommet is
unavailable, be sure to install a rubber
grommet to protect the wires.

• Connect a short GND wire from BassLink II to
the nearest bare metal surface. For a good
connection, sand away paint from the metal
surface and use a screw with a (star) lock washer.

Figure 5. Power connections for BassLink II.

• Install a fuse holder with a 25A fuse within 18"
of the battery + terminal (see Figure 5).

• The REM connection requires +5 to +12 Vdc
for BassLink II to turn on remotely. Most head
units with preamp outputs provide this remote
voltage signal. For speaker-level applications,
a remote connection is not required, since
BassLink II’s Auto Turn On feature will sense
voltage on the speaker wires to automatically
turn on BassLink II.

IMPORTANT: To enable BassLink II’s Auto
Turn On feature, set AUTO TURN ON to the
AUTO position (see Figure 15 on page 6).

APPLICATIONS

BassLink II is equipped with four line-level (RCA)
inputs and four speaker-level inputs. Any combina­tion of line-level and speaker-level inputs may be
used to provide nonfading bass when connected to
a head unit with four outputs.

Figure 6. BassLink II audio connections for a head
unit with two line-level or subwoofer (RCA) outputs.

To help you plan your installation, we have
included three system applications in Figures 6
through 8. For more system ideas, see your
authorized Infinity car audio dealer.

Note: The applications show the REMOTE LEVEL
control, which installs under the dashboard for
easy in-car bass level adjustments (see page 7).

®

LF Speaker

+–

RF Speaker

LR Speaker RR Speaker

+–

+–+–

Source Unit

BassLink II
(right side)

+–

RCA Stereo Cables

(not supplied)

BassLink II
(right side)

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APPLICATIONS (CONTINUED)

Figure 7. BassLink II audio connections for a head
unit equipped with four line-level (RCA) outputs.

Figure 8. BassLink II audio connections for a head
unit equipped with four speaker-level outputs.

Left Front Right

Left Rear Right

+

– –

– –

+

+

+

Left Front Right

+

– –

+

BassLink II
(right side)

LF

+

–

RF

–

+

LR

+

–

RR

–

+

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BASSLINK 4SC INSTALLATION

DESCRIPTION

The BassLink 4sc is a plug-and-play amplifier
designed to make upgrading your system easy.
The BassLink 4sc is designed to slide into an
available slot in the BassLink II. Unlike an
additional outboard amplifier, the BassLink 4sc
doesn’t require any additional space. The
BassLink 4sc also includes a Phantom Center
effect, which creates the illusion of a center
channel even if no center speaker is installed.

INSTALLATION

1. Remove the wiring cover from BassLink II.

2. Remove the eight screws that hold the
AMPLIFIER DOCK cover panel in place
(Figure 9). Save the screws.

3. Remove the screw that attaches the two
wiring harnesses and connectors to the panel.

4. Connect the wiring harness connectors to the
appropriate connectors on the BassLink 4sc’s
circuit board. See Figure 10.

5. Insert the amplifier and install the eight
screws that were removed in Step 2. See
Figure 10.

6. Install 40A fuse at the battery.

Note: All four inputs on BassLink II must be used
in order for the BassLink 4sc amplifier to function
properly.

Figure 9.

Figure 10.

CONNECTIONS

Connect the front and rear speakers as shown in
Figure 11.

Figure 11.

SETTINGS

The BassLink 4sc has input level control for the
front and rear speakers and PHANTOM CENTER
controls.

For proper setup, please refer to the full
BassLink 4sc owner’s manual.

Figure 12.

APPLICATION

Figure 13. Typical installation using all four speaker­level inputs from the source unit.

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CONTROLS AND FUNCTIONS

BassLink II provides several controls and indica­tors that simplify sonic integration with virtually
any vehicle’s unique acoustic properties. They are
located on the front and side panels, as shown in
Figures 14 and 15.

Figure 14. BassLink II controls on the front panel.

POWER LED:This indicator will glow blue when

BassLink II is operational.

GAIN Control: Use this control to adjust the rela­tive volume (loudness) of BassLink II with respect
to the other speakers in the vehicle.

CROSSOVER: Use this control to adjust the
amount of high-frequency information present in
BassLink II’s output. A lower value means more of
the high frequencies are filtered out.

BASS BOOST: Use this control to correct any
perceived peak or dip in the bass response
(typically around 40Hz in most vehicles). Set the
control to any value between –6dB and +3dB,
according to what sounds best.

Figure 15. BassLink II controls on right-side panel.

PHASE Control: Use this switch to reverse the

phase of BassLink II’s output with respect to
its input. Choose the position (0° or 180°) that
sounds the best.

Note: Depending on BassLink II’s orientation and
location in a vehicle, reversing the phase may,
or may not, increase or decrease the amount
of upper bass being reproduced.

AUTO TURN ON: For speaker-level connections,
use this switch to activate (or deactivate) BassLink
II’s automatic turn-on circuit. For most speaker-level
applications, slide the switch to AUTO. However, if
your system produces false turn-on signals or uses
a remote (REM) connection, slide the switch to OFF.

REMOTE LEVEL Control: Use this RJ11 jack to
connect the REMOTE LEVEL control (see page 7).

SERVO LED: This indicator glows blue when the
subwoofer is at maximum excursion and the
amplifier is modifying the output to maintain
maximum performance. Be sure to monitor this
indicator during BassLink II setup (see Tuning
BassLink II). When properly tuned, the SERVO LED
should light momentarily during high-level bass
transients. Avoid adjustments that cause the LED
to remain lit for extended periods.

TUNING BASSLINK II

1. Unplug the RJ11 cable that connects the
REMOTE LEVEL control to BassLink II.

2. Make sure the head unit is off and its volume
control is set to minimum.

3. On BassLink II’s front panel, initially set
all controls to their midpoint positions, as
shown in Figure 14. On BassLink II’s side
panel, initially set PHASE to 0°, as shown
in Figure 15.

4. Turn on the head unit and play a favorite
music track that has substantial bass. Set the
head unit’s volume control to 75 percent of
the total output (approximately 3 o’clock on
rotary controls).

5. Adjust the GAIN control clockwise until the
SERVO LED (on BassLink II’s side panel)
begins to flash with each bass note but
doesn’t stay lit continuously.

6. Listen to your system, making a mental
note of the amount of upper bass being
reproduced.

7. Switch the PHASE control to 180° and listen
again for upper bass content. There may be
more upper bass, less upper bass, or no
change at all. The position that provides the
most upper bass is correct, but choose either
setting according to your taste.

8. Adjust the CROSSOVER control clockwise
or counterclockwise until you hear only low­frequency information. For example, you
should NOT hear any vocals coming from
BassLink II when seated in the normal listen­ing position.

9. Adjust the BASS BOOST control clockwise or
counterclockwise to suit your taste.

10. Recheck the SERVO LED to make sure it’s
flashing in time with the bass but is not lit
continuously. If it is lit continuously, adjust
the GAIN control counterclockwise until the
SERVO LED only flashes in time with the bass.

11. Reconnect the RJ11 cable between the
REMOTE LEVEL control and BassLink II. You
may then use the REMOTE LEVEL control to
adjust the level of the bass to suit your taste
and/or different program material.

Note: In most cases, the above steps will provide
satisfactory tuning. However, the actual process
may require several readjustments of each control,
since the settings will interact with each other.
If necessary, consult your authorized Infinity
car audio dealer for help in tuning your system.

6

INSTALLATION

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Powered Subwoofer Basslink II

CONNECTING THE REMOTE LEVEL
CONTROL TO BASSLINK II

OPERATION

The REMOTE LEVEL control may be mounted
under the dash or may be dismantled and
mounted in the dash for a factory appearance.

UNDER-DASH MOUNTING

Select a mounting location that allows easy
access to the control while driving. Using the
REMOTE LEVEL control as a template, mark and
drill holes in the mounting surface. Attach the
REMOTE LEVEL control using the mounting
screws provided (Figure 16).

Figure 16. Under-dash mounting of the REMOTE
LEVEL control.

Route the cable behind the dash or other interior
panels and under the carpet. Do not route the
cable outside the vehicle. Connect the RJ11 cable
between the RJ11 receptacle on the BassLink II
and the receptacle on the REMOTE LEVEL control
(Figure 17).

Figure 17. REMOTE LEVEL control electrical
connection.

The REMOTE LEVEL control is used to adjust the
output level of the subwoofer. This level control
allows you to reduce the subwoofer output for
music with heavy bass content and increase the
level for music with less bass content.

PHANTOM CENTER Switch:The REMOTE LEVEL
control has a three-position switch that is used
when the BassLink 4sc amplifier is installed.
Please refer to the BassLink 4sc owner’s
manual for the specific operation of this switch.

TROUBLESHOOTING

Capacitor

+ Speaker wire 
from head unit

To + speaker-level
input on BassLink II

To + speaker lead

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Powered Subwoofer Basslink II

BassLink II (4sc, if installed)

• PROBLEM:
POWER LED not lit.

CAUSES and SOLUTIONS:

1. Fuse is blown and needs replacement.

2. Head unit not functioning properly. Check

remote voltage, and power, ground or
remote connections.

• PROBLEM:
POWER LED is lit but there is no bass.

CAUSES and SOLUTIONS:

1. Inputs are not connected. Check connections.

2. Head-unit fader control is not set properly.

Adjust head-unit fader control to feed audio
signals to BassLink II.

• PROBLEM:
BassLink II sounds muddy or distorted.

CAUSES and SOLUTIONS:

1. Gain is set too high and SERVO LED is lit

constantly. Readjust GAIN control (see
Tuning BassLink II on page 6).

2. Bass is set too high. Readjust BASS BOOST

control (see Tuning BassLink II on page 6).

3. Head-unit output is distorted or blown. See

your authorized Infinity car audio dealer.

• PROBLEM:
No output from BassLink II when head-unit
fader control set to front or rear (in a 4-channel
connection).

CAUSE and SOLUTION:
Input connections are improperly wired. Verify
all connections (see Applications starting on
page 3).

• PROBLEM:
BassLink II turns on before head unit is com­pletely on and produces a “thump” sound.

CAUSE and SOLUTION:
For speaker-level connections, head unit is
producing a false turn-on signal. On BassLink
II’s side panel, slide AUTO TURN ON to OFF.

• PROBLEM:
BassLink II’s POWER LED remains on after head
unit is turned off.

CAUSE and SOLUTION:
For speaker-level connections, this is normal
operation when AUTO TURN ON is set to ON.
BassLink II will remain on another 5 to 10 min­utes after sensing that audio signals are not
present before shutting down.

• PROBLEM:
BassLink II produces a loud humming noise
with the system OFF when using speaker-level
inputs.

CAUSE and SOLUTIONS:
This problem is caused by a feedback loop
between your speakers and the high-level inputs
of BassLink II.

Choose one of the following solutions:

1. Connect a wire from the REMOTE terminal on
BassLink II to the remote turn-on of your head
unit or to the vehicle’s accessory circuit. On the
control panel, slide the AUTO TURN ON switch
to the OFF position.

2. Connect the supplied capacitors between

each of the speaker outputs of the head unit
and the speaker’s positive lead, as shown
in Figure 18. Connect each positive lead of
BassLink II’s high-level inputs to the head-unit
side of the capacitors. Use one capacitor per
speaker input channel.

Figure 18. Connecting supplied capacitors.

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BASSLINK II DISASSEMBLY

1) Remove “Amplifier Dock” cover; (8) Phillips screws.

2) Remove (10) Phillips screws holding main heatsink/amplifier to enclosure,
tapping the heatsink with a rubber mallet may be necessary to loosen it. Pull
amplifier from enclosure

3) Remove single 12 pin Molex connector M300 and both pairs of FASTON
terminals from the amplifier PCB; do not mix up the two pairs of red/black wires
(speaker and A/B). Label if necessary.

4) With the screw cavities facing upwards on the enclosure, remove the (12) Phillips
screws holding the enclosure together.

5) Using the opening of the “Amplifier Dock” as leverage, separate the enclosure
halves; to completely separate the wiring, remove the 8 pin Molex connector
M200 from the Jack/Limiter PCB.

6) If the Gain PCB (Gain/Xover/Base pots) needs to be accessed, there is an
additional screw holding the plastic cover on, besides the two exposed ones, that
must be removed and is visible after removing the 10" passive radiator (8 Phillips
screws)

7) The Jack PCB is not serviceable, as it is attached to the enclosure with adhesive.

8) Reassembly: follow in reverse order, and be sure to not mix the red/black wire
pair (speaker and A/B) on the MAIN PCB when you connect them to the
FASTON terminals.

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Ref # Description Part Number Qty

EXPLODED VIEW

1 Infinity Logo 316-000-00130-1BA 2
2 Grille 329-100-05125-0VA 2
3 Screw M6*25 Black 351-AM06025A946 8
4 Screw T4*25 Black 352-AM04025D964 16
5 Front baffle 372-000-05027 1
6 Woofer F25X12PR-03DW-P 1
7 Gasket 333-EVA-05142-0BA 1
8 PVC label 315-PC-05035-0TAE 1

9 Side Cover 305-PC-05007-0BA 1
10 Plastic Control Cover 305-PC-05008-0BAE 1
11 Screw M3*12 Black 351-AM03012A090 8
12 Grommet 335-NYL-05012-0WA 1
13 Rubber Cover Retainers 338-RUB-05027-0BA 4

2.6 ohm DCR

14 Metal Insert 339-FE-05015 4
15 Passive Woofer PR-255008-P 1
16 Back Baffle 372-000-05028 1
17 Rubber Cork 338-RUB-05029-0BA 8
18 Screw M4*15 Black 351-AM04015A947 10
19 Heat Sink 011-7525-00580 1
20 Screw M3*12 Black 352-CM03012D076 1
21 Gasket 333-EVA-05139-0BA 12
22 Metal Insert 339-FE-05014 5
23 Screw M3*12 Black 352-AM03012D831 3
24 Cover 398-PC-05128 1
25 Light Pipe 398-PC-05127 1
26 Screw M4*12 Black 352-HM04012D319 9
27 Control PCB 1
28 Knob Gain/Xover/Base 015-7500-00130 3