Infinity 1210-A, 1211-A Service manual

Reference Series

1210a
1211a

1 CHANNEL POWER AMPLIFIER

SERVICE MANUAL

Infinity Systems, Inc.

250 Crossways Park Dr.

Woodbury, New York 11797 Rev

2aa10/2005

Power Amplifier Reference 1210a/1211a

1

- CONTENTS -

SPECIFICATIONS ………………………………….……..1

FEATURES/TEST CONDITIONS……..…………………2

CONTROLS/CONNECTIONS………….……..…...…..…3

INSTALLATION………………….……...……..…...…...…5

BASIC TROUBLESHOOTING..…….…….………………7

TYPICAL SYSTEM WIRING..…….…….……………..…8

EXPLODED VIEW/PARTS LIST………………………....9

MECHANICAL PARTS LIST…………………………….10

AMPLIFIER BLOCK DIAGRAM…………………………11

P.C.B. DRAWINGS….…………………………………….12

ELECTRICAL PARTS LIST ……………………………. 16

REF 1211a ELECTRICAL PARTS LIST ADDENDUM…...…20

IC/TRANSISTOR PINOUTS..…………………………….21

REF 1210a SCHEMATICS………..…………..……..…..27

REF 1211a SCHEMATICS………..……………………..30

PACKING……………………….…………………………33

Reference 1210a/1211a Specifications

Output Power: 854W RMS x 1 @ 4 ohms; ≤1% THD + N
(14.4 VDC) 1300W RMS x 1 @ 2 ohms; ≤1% THD + N
Signal-to-noise ratio: 72dBA (reference 1W into 4 ohms)
Dynamic power: 1516W channels @ 2 ohms
Effective damping factor: 6.357 @ 4 ohms
Frequency response: 17Hz – 302Hz (-3dB)
Maximum input signal: 5.7V
Maximum sensitivity: Reference 1210a - 260mV

Reference 1211a - 75mV

DC Offset <50mV (-50%)
Output regulation: .132dB @ 4 ohms
Idle Current 2.8A
Input Impedance 22kΩ
Max Current Draw 70A @ 4 ohms

125A @ 2 ohms
Dimensions: 12 x 18 1/2 x 2 11/16” (L x W x D)
(305mm x 470mm x 68mm)
Fuse: 3 x 40A

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.

Power Amplifier Reference 1210a/1211a

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Features

x 1-Channel Operation
x Advanced MOSFET Oversized Floating Rail Power Supply
x Floating Ground Factory
x Variable lnput Sensitivity (250mV
x Fully Complementary Output Stage with Class-D Voltage Amplification
x Gold-plated Power, lnput and Output Connectors
x 2-Ohm Stable

- Head - Unit Speaker - Level input

- 6V)

Test Conditions and Notes

x All tests to be done, unless otherwise specified, from 10Hz to 302Hz at 14.4V DC

into 2 ohm loads and adjust the units gain so that with a .250 volt input signal the
unit is at Its maximum rated output. All measurements will be done using an
Audio precision system one and the supply voltage.

x An A+ line voltage of 14.4V DC shall be applied to the unit under test for all

measurements unless otherwise specified. The voltage applied to the unit shall
be measured at the power connection on the Amplifier.

x Signal Source

Unless otherwise specified, all tests shall be conducted with the Audio Signal
Generator output configured to be balanced, less than or equal to 50 ohm source
impedance, and floating. The signal source "GND" shall be connected to the
Amplifier PWR GND at the Amplifier.

x Output Load

Unless otherwise specified, all tests shall be conducted with 2 ohm resistive
loads having less than 10% reactive components at any frequency below 302Hz.
Each resistor shall have a value that remains within 1
rated output of the unit under test.

x Power Indicator Green LED steadily illuminates for normal operation. Illuminates

up Red LED blinks when protection circuitry is engaged, and during power up.

% while dissipating the

The Reference amplifiers are capable of
delivering high power levels, and require a
reliable connection to the vehicle’s electrical
system in order to perform optimally. See
Figure 1 for connection location. Please
adhere to the following instructions carefully.

GROUND CONNECTION

Connect the amplifier’s Ground (GND) terminal
to a solid point on the vehicle’s metal chassis,
as close to the amplifier as possible. Refer to the
chart below to determine minimum wire-gauge
size. Sand away any paint from this location; use
a star-type-lock washer to secure the connection.

POWER CONNECTION

Connect a wire (see chart at right for appropriate
gauge) directly to the vehicle’s positive battery
terminal, and install an appropriate fuse holder
within 18" of the battery terminal. Do not
install the fuse at this time. Route the wire to
the amplifier’s location, and connect it to the
amplifier’s positive (+12V) terminal. Be sure to
use appropriate grommets whenever routing
wires through the firewall or other sheet metal.
Failure to adequately protect the positive wire
from potential damage may result in a vehicle
fire. When you are done routing and connecting
this wire to the battery and to the amplifier,
you may install the fuse at the battery. The
fuse value should be selected based on total
amplifier-current draw; see chart at right.

REMOTE CONNECTION

Connect the amplifier’s Remote (REMOTE)
terminal to the source unit’s Remote Turn-On
lead using a minimum of 18-gauge wire. If your
source unit does not have a remote turn-on
connection, connect the amplifier’s (REMOTE)
terminal to the vehicle’s accessory circuit.

SPEAKER CONNECTIONS

Refer to the application guides on the pages
that follow. Speaker connections should be
made using a minimum of 16-gauge wire.

NOTE: When using the low-level or high-level
inputs, the AUX outputs can be used to pass a
full-range line-level signal to another amplifier.

POWER CONNECTIONS

Figur

e 1

.

T

erminal-connection end plate.

Power Amplifier Reference 1210a/1211a

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WIRE-GAUGE CHART

Amplifier Maximum Minimum
Model Current Draw Wire Gauge

AWG
AWG

1210a/1211a 115A #4 AWG

These recommendations assume 7' – 10' wire
runs. If your installation differs markedly, you
will need to adjust the wire gauge accordingly.

Figure 4. Reference subwoofer amplifier with one woofer connection.

Figure 3. Reference subwoofer amplifier with two woofer connections.

The Reference subwoofer amplifiers are
single-channel amplifiers. There are two sets of
terminals to make it easy to connect multiple
woofers. Either set of (+/–) terminals may be
used when connecting woofers.

To the right are two application diagrams to help
plan your subwoofer system installation. Figures
3 and 4 show how to configure the Reference
subwoofer amplifiers (models 311a, 611a and
1211a).

NOTE: For simplicity, Figures 3 and 4 do not
show power, remote and input connections.

NOTE: Minimum speaker load is 2 ohms.

Power Amplifier

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Reference 1210a/1211a

A

PPLICATIONS

– 1201a/1211a

SETTING INPUT SENSITIVITY

1. Initially turn the INPUT LEVEL control(s) to
minimum (counterclockwise).

2. Reconnect the (–) negative lead to the vehi-

cle’s battery. Apply power to the audio system
and play a dynamic music track.

3. On the source unit, increase the volume

control to 3/4 volume. Slowly increase the
INPUT LEVEL control(s) toward three o’clock
until you hear slight distortion in the music.
Then reduce the INPUT LEVEL slightly until
distortion is no longer heard.

NOTE: After the source unit is on, blue LEDs (on
the top panel) will light, indicating the amplifier
is on. If not, check the wiring, especially the
remote connection from the source unit. Also
refer to “Troubleshooting” on page 7.

REMOTE LEVEL CONTROL (OPTIONAL)

All three Reference subwoofer amplifiers and
the 5761a amplifier have inputs for an optional
remote level control (100rc). This will allow the
subwoofer level to be adjusted from the listening
position. Connect the optional remote level
control using the RJ-11 jack on the side of the
amplifier. Install the control module in the front
of the vehicle within easy reach of the driver.
Both the underside of the dash and the center
console are suitable locations. Refer to the
mounting instructions accompanying the 100rc.

AUX OUTPUT

Reference amplifiers (except 5761a) are equipped
with full-range outputs that can be used to
connect additional amplifiers.

NOTE: When using the low- or high-level inputs,
the AUX outputs can be used to pass a full-range
line-level signal to another amplifier.

Figure 13. Control end panel.

Power Amplifier

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Reference 1210a/1211a

STATUS LEDs
Clip: Indicates the amplifier is being overdriven,

and your speakers may be in danger. This
should blink only on musical peaks, and not
be on constantly.

Power: Indicates the amplifier is on.
Protection: Refer to “Troubleshooting” for specific

indications.

Figure 15. LED status.

SETTING DBO

™

(310a, 610a and 1210a)

The Dynamic Bass Optimizer (DBO) is used to
enhance low-frequency reproduction in a vehicle.
Conventional bass-boost circuits only increase
bass at a fixed frequency, and cause the amplifier
to consume considerable power. The DBO allows
you to adjust the frequency (20Hz – 80Hz) as well
as the boost level (up to 12dB; see Figure 14),
allowing you to fine-tune the bass in your system
to optimize performance.

For sealed enclosures, the DBO can be used
to enhance the lower bass region of sealed
enclosures.

For bigger/fuller bass, adjust the HP FREQ
between 35Hz and 45Hz; adjust the BOOST
control according to your preference.

For tighter-sounding bass, adjust the HP FREQ
between 45Hz and 55Hz; adjust the BOOST
control according to your preference.

For vented enclosures, the DBO should be used
as a subsonic filter to reduce overexcursion
of the woofers. Set the HP FREQ control 10Hz
below the tuning frequency of the enclosure
(e.g., 25Hz for a box tuning of 35Hz); adjust the
BOOST control to taste. This will conserve
amplifier power typically wasted on frequencies
below the tuned frequency of the enclosure.

For infinite-baffle applications, set the HP FREQ to
the speaker’s Fs value (reducing overexcursion of
the woofer); adjust the Boost control to taste.

Figure 14. Frequency-response curves show
typical DBO control ranges.

INSTALLATION AND SETUP (CONT.)

-9

-6

-3

0

-12
20 80

Freq. (Hz)

dB

DBO HP FREQ Control

(adjusts cut-off

frequency)

HP FREQ

100Hz20Hz

-6

0

6

12

-12
20 80

Freq. (Hz)

dB

DBO BOOST Control

(adjusts boost amount

at cut-off frequency)

BOOST

MAX MIN

Power Amplifier Reference 1210a/1211a

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•

PROBLEM:

No audio (POWER LED is off).

CAUSE and SOLUTION:
No voltage at BATT+ and/or REM terminals, or
bad or no ground connection. Check voltages
at amplifier terminals with VOM.

•

PROBLEM:

No audio (PROTECT LED flashes every
4 seconds).

CAUSE and SOLUTION:
DC voltage on amplifier output. Amplifier may
need service; see enclosed warranty card for
service information.

•

PROBLEM:

No audio (PROTECT LED is on).

CAUSE and SOLUTION:
Amplifier is overheated. Make sure amplifier
cooling is not blocked at mounting location;
verify that speaker-system impedance is within
specified limits.

•

PROBLEM:

No audio (PROTECT and POWER LEDs flash).

CAUSE and SOLUTION:
Voltage less than 9V on BATT+ connection.
Check vehicle charging system.

•

PROBLEM:

No audio (PROTECT LED is on).

CAUSE and SOLUTION:
Voltage greater than 16V or less than 8.5V on
BATT+ connection. Check vehicle charging
system.

•

PROBLEM:

Distorted audio.

CAUSE and SOLUTION:
Input sensitivity is not set properly, or amplifier
or source unit is defective. Check INPUT LEVEL
setting, or check speaker wires for shorts or
grounds.

•

PROBLEM:

Distorted audio (PROTECT LED flashes).

CAUSE and SOLUTION:
Short circuit in speaker or wire. Remove
speaker leads one at a time to locate shorted
speaker or wire, then repair.

•

PROBLEM:

Music lacks “punch.”

CAUSE and SOLUTION:
Speakers are not connected properly. Check
speaker connections for proper polarity.

TROUBLESHOOTING

Power Amplifier Reference 1210a/1211a

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Power Amplifier Reference 1210a/1211a

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Reference 1210a/1211a

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Power Amplifier Reference 1210a/1211a

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