Linear Power MODEL 2120 Programming manual

F O R T H E L O V E O F M U S I C
™
MODEL 2120©
STEREO BI-AMPLIFIER
OWNER'S MANUAL AND
INSTALLATION GUIDE
INTRODUCTION
The 2120©contains essentially four separate electronic components housed in a
single chassis; a 120-watt RMS mono amplifier to drive the Bass Vent©
subwoofer, a 120-watt RMS stereo amplifier, and two variable phase coherent
electronic crossovers. Streamlined installation, systems versatility, modular
expandability, and phase coherency are some of the key features that highlight
the Model 2120©.
Like all Linear Power™ amplifiers, the 2120©incorporates the Infinitely
Variable Gain Adjustment which allows the user to match the amplifier
precisely to almost any deck on the market whether the output is pre-amp or
speaker level. Follow the instructions in this book under
OPERATION/ADJUSTMENT for adjustment of the gain control.
The LINEAR POWER™ Model 2120© Bi-Amplifier employs a sophisticated
design combining reliability, high power, low distortion, and freedom from
external noise. When properly installed, it will give long and faithful service.
When combined with other high quality components, it will be the heart of a
superb system.
WE STRONGLY RECOMMEND THAT THE INSTALLATION BE DONE BY A
PROFESSIONAL AUTOSOUND INSTALLER.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 1

TECHNICAL DESCRIPTION
POWER SUPPLY: Self oscillating for reliability and efficiency. The transformer is
epoxy dipped for extreme vibration resistance.
OUTPUT STAGES: Transformer less, direct coupled and fully complimentary.
Output transistors are high current and low distortion TO-3 Devices in the 3001©,
operating at a fraction of their limitations. Total power dissipation potential of the
output transistors is well over 1000 watts.
PROTECTION: Our stable amplifier design is made virtually indestructible by two
separate forms of protection. First is an all-new Thermal Protection Circuit, which
is designed to prevent damage from high frequency oscillations or excessive
ambient temperature. The second form of protection protects the amplifier from
short circuits in the installation. Both circuits are automatically resetting.
CONSTRUCTION FEATURES: The infinitely variable input sensitivity control
permits optimal signal matching for lowest noise and lowest distortion with
virtually any source. All components used are rated for at least 150% of their
intended use, and are mounted on double-sided fiberglass epoxy circuit boards.
QUALITY CONTROL: In-house construction of critical components like
transformers and chassis pieces, as well as total assembly, allows LINEAR
POWER™ to maintain uniform quality. 100% of the finished units are tested, then
burned in for four hours, and tested again. Amplifiers, which pass these rigorous
controls, have truly earned the LINEAR POWER™ Logo.
INSTRUCTIONS
Read the following instructions through completely. If they appear too
complicated we recommend you have an authorized Linear Power™ Dealer do
the work.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 2

FEATURE/DESCRIPTION
A. The High Pass Filter
This filter is screwdriver adjustable with a continuously variable range from
300Hz to 1.7Hz. In the fully counter-clockwise position, the stereo main amplifier
is rolled off at 300Hz. This filter may only be activated when switch "B" is moved
in the direction of the filter or "TRI" position. When this filter is operational the
120-watt stereo amp becomes essentially a band pass amplifier. A low level
signal from phono plug set "H" provides output above the selected crossover
point of the high pass filter so that a second amplifier may be added to complete
the tri-amplified sound system.
B. The Operational Mode Activating Switch
The switch determines whether the 2120©will operate as a bi-amplifier or a
modular tri-amp. Move this switch with a small screwdriver in the direction of the
filter you wish to activate. To the right, or "Bi" position, only the low pass filter (C)
is functional. To the left, both filters become operational.
C. The Low Pass Filter
Screw driver adjustable with a continuously variable range between 45 to 200
Hz. Fully counter-clockwise is 45Hz. With the 2120©operating in the bi-amp
mode, low-level output is provided from plug set 'H' above the selected crossover
point of the low pass filter to beyond 20KHz. This feature allows any smaller
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 3

Linear Power™ amplifier to power 'front fill' drivers in the automobile. With this
type of application, the 'font fill' amplifier and speakers see no low bass material.
Cone distortion is drastically reduced, while efficiency is vastly increased.
D. Subwoofer Amplifier Gain
This control provides gain to the 120-watt mono subwoofer amplifier.
Accentuation or attenuation of +-12dB is possible with this control. The purpose
of this control is to adjust the output of the subwoofer system relative to the
efficiency of the main speaker system.
E. Master Gain Control
This control is found on all Linear Power™ amplifiers. The master gain control
matches the output of any deck to the input of the 2120©. Fully counter-clockwise
if minimum gain. Proper adjustment procedure is found under
OPERATION/ADJUSTMENT.
F. 120 Watt Mono Subwoofer Output
To the Bass Vent©or any other dual speaker subwoofer system, Grey= right(+),
Green= left (+), Black is ground. The mono output amplifier is internally
paralleled to see a two-ohm load when used with two, four-ohm drivers. This
is done for higher current capability, and superior woofer control. For single
subwoofer use, connect both the green and gray wires to the speaker (+) and
both black wires to speaker (-). The ideal configuration is two, 4-ohm woofers.
When connected to a single four-ohm woofer full power will not be developed.
G.120 Watt Stereo Output
Grey = right (+), Green = left (+), Black = ground.
H. Low level Outputs
In bi-amp or tri-amp operation low level output (at unity gain) is always provided.
In the bi-amp mode output from the selected subwoofer crossover point to
beyond 20KHz is provided to the output plugs. In the tri-amp mode, output is
provided above the selected crossover point of the high pass filter to beyond
20KHz.
I. Input Signal from Source Unit
MOUNTING
1. The amplifier will work best if it is kept as cool as possible. Mount in a position
that allows air to flow freely through the black fins. Be sure there is ample space
above the amplifier. The amplifier should not be mounted upside down. Avoid
mounting the amplifier in the dash or on the firewall to avoid noises being
radiated directly into the case.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 4

2. Mount your amplifier in a position that allows ample room for gain adjustments,
and the installation, removal, and attachment of all leads.
3. The case of your amplifier is designed to act as a noise shield. To maintain
this protection, be sure the metal case of the amp does not touch the metal of the
car. Do not remove or damage the rubber grommets, which provide electrical
insulation and vibration isolation.
WIRING
1. Fuse: A fuse of the proper size must be installed in line with the main
power in order to prevent possible damage to the vehicles wiring. It should
be connected to the battery positive terminal or as close to the battery as
possible. Use the fuse holder and fuse provided and replace only with the
same size and type of fuse. Use AGC 30. WARNING: OVERFUSING
WILL DAMAGE THE AMPLIFIER.
2. Main Power: The free end of the fuse holder wire should be connected to the
large RED wire from the amplifier. IMPORTANT: Solder all connections!
3. Main Ground: Connect the large BLACK wire directly to the battery negative
terminal.
4. Remote Turn on: The RED and WHITE wire is not a main power source for
the amplifier, but acts as an electrical switch to turn the amplifier on and off. It
should be connected to the power antenna lead from the radio. Where no power
lead exists, a source of +12 volts connected through a toggle switch will do. DO
NOT CONNECT DIRECTLY TO A SOURCE THAT WILL LEAVE THE
AMPLIFIER PERMANENTLY ON, AS THIS WILL DRAIN THE BATTERY.
5. Signal Input: The RCA (Phono) Jack inputs will accommodate either high or
low level signals, ranging from 180mV to 5 volts. For use with a high level source
that is intended to drive speakers directly, attach the speaker leads to male RCA
plugs and insert into the inputs. NOTE: The positive speaker lead should always
connect to the center pin of the RCA plug.
6. Speaker Outputs
(a). The speaker fanout connector on the left, marked 'sub', is a 120-watt mono
output.
Connect the GREY wire to the RIGHT speaker (+) terminal.
Connect the GREEN wire to the LEFT speaker (+) terminal.
Connect one of the BLACK wires to the RIGHT speaker (-) terminal.
Connect the other BLACK wire to the LEFT speaker (-) terminal.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 5

(b). The speaker fanout connector on the right, marked 'main/mid-bass', is the
stereo output.
Connect the GREY wire to the RIGHT speaker (+) terminal.
Connect the GREEN wire to the LEFT speaker (+) terminal.
Connect one of the BLACK wires to the RIGHT speaker (-) terminal.
Connect the other BLACK wire to the LEFT speaker (-) terminal.
OPERATION/ADJUSTMENT
DO NOT apply power to the system until the installation is complete, and the
following steps 1 and 2 have been performed.
1. Be certain that all gain controls on each component have been turned down.
2. Set all crossovers a point well within the defined frequency parameters of the
drivers. The speaker manufacturer will supply frequency response data with their
driver.
3. Apply power to the system. The Amp(s) will turn on after a slight delay. To
properly adjust the master gain control of the 2120©we suggest the following
technique: Slowly turn the volume up on your source unit until you hear it just
start to distort, then back it down just below that point. That is a loud as you
should ever play it for quality sound. Now, slowly increase the master gain on the
2120 until either the speakers distort from excess power, or, the amp distorts
from input overload. At either point, slightly decrease the gain control on the amp
and a perfect input/output match has been achieved. After the master gain has
been properly adjusted, use the same procedure to adjust the sub-level control.
Some source units with extremely low output levels will require a LINEAR
POWER™ PA2©to boost the output to the necessary proper level.
NOTE: IT IS VERY IMPORTANT THAT THE GAIN CONTROL BE TURNED AS
FAR DOWN AS POSSIBLE IN ORDER THAT UNWANTED ENGINE NOISE BE
KEPT TO A MINIMUM.
SYSTEM FINE TUNING
Now that the gain controls have been properly set, the system is ready to be "fine
tuned". Always tune a multi-amp/driver system from the bass up. In a bi-amp
system, the subwoofer crossover should be varied until the smoothest low
frequency response has been obtained. Tri-amping is a more sophisticated
process of sound reproduction and hence requires more time to properly design
and fine tune. Keep in mind that a poorly designed tri-amplified sound system
may yield lower sound quality than a well executed bi-amped system.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 6

NOISE NOTES
Unwanted noise is the worst single problem encountered in automotive amplifier
installations. Several basics must be kept in mind when preventing noise
problems.
1. Use shielded cables whenever a preamp level music source is used.
2. All connections must be tight and free from corrosion, paint, etc., and
insulated.
3. Route all signal cables away from existing wiring in the vehicle.
4. If possible, avoid mounting the amplifier in the dash or on the firewall, as noise
may be induced due to the proximity of noisy wiring and switches.
GENERAL TROUBLESHOOTING
NO SOUND
Check all connections. Check main power fuse. Check accessory fuse. With a
trouble light or meter, be sure +12V is present at the amplifier on the large
positive cable and on the small red/white turn-on wire. Check for a good ground
connection. Check by substitution or other method for proper operation of music
source.
BLOWS FUSES
Check all connections to be sure all power wires and speaker wires do not touch
ground or each other. Re-check polarity of main power wires.
SHUTS OFF
As this amplifier is equipped with a thermal and a short circuit shut-down system,
in the unlikely event of excessive temperatures due to high ambient temperature
or improper speaker impedance, the amp will turn itself off. To avoid damage to
the speakers, turn the volume to a minimum while waiting for the amp to turn
itself back on.
SERVICE OR REPAIR
To obtain modification, service or repair, please contact our ONLY Authorized
LINEAR POWER™ Product Service Center:
T.I.P.S. INC.
3455 Lanell lane, Pearl, MS 39208
[phone]
E-mail: [email protected]
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™
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 7

SPECIFICATIONS
2120©
Main Amplifier: 60 Watts per channel minimum continuous average power into four
ohms. Both channels driven from 300Hz to 20KHz with no more
than 0.15% total harmonic distortion.
Subwoofer
Amplifier:
120 watts minimum continuous average power output into two
ohms, mono from 20Hz to 200Hz with no more than 0.15% total
harmonic distortion.
Inter-modulation
Distortion: 0.1%
Frequenc
y
Response: -3dB from 12 to 150,000 Hertz
Si
g
nal to Noise
Ratio: 95dB or greater (A-Weight)
Slew Rate: 13 volts per microsecond
Crossover Phase
Shift: +/- 2.8 degrees maximum
Current Draw: 1.5 amperes at idle. 30 amperes at maximum RMS test conditions.
Input Si
g
nal for
Maximum Power: 0.2 volts at maximum gain setting. 5 volts at minimum gain setting.
D
y
namic
Headroom: 2dB
Damping Factor: 200 at all frequencies.
Dimensions: 7 1/4" x 13 1/2" x 4 1/8"
™
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© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc. 8