Linear Power PA II User manual

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F O R T H E L O V E O F M U S I C
MODEL PA II©
(1995-MSRP $399.00)
OWNER'S MANUAL AND
INSTALLATION GUIDE
INTRODUCTION
After countless hours of analyzing the performances of existing car audio
systems, it became obvious that certain areas of the audio spectrum needed
help. Even with some of the best equipment being utilized in carefully designed
systems, the sonic performance usually falls short of ideal. Something was
needed to fill the gap and derive optimum performance from this equipment.
Enter the Linear Power™ PA-II©.
The PA-II©was engineered to optimize the impedance mismatches possible with
all types of equipment, and to provide the equalization necessary to correct for
the shortcomings of speakers used in the mobile environment.
The PA-II©is a four-band equalizer and a preamp stage with up to 32db of gain,
a preamp level clipping indicator, a patch back fader, and an amplifier turn on
lead.
This unit when used in conjunction with almost any component car audio system
will dramatically improve the dynamics, clarity, signal to noise ratio, and the
overall performance of the whole system.
The physical size was painstakingly kept to a minimum to aid in the installation of
the PA-II©in even the most restricted vehicles and the backlighting features
makes nighttime operation safer and easier.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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TECHNICAL DESCRIPTION
In order to reach the high line level voltage desirable at the output of the PA-II©,
and to isolate the preamp from the vehicle's electrical system in the interest of
eliminating noises, a self-oscillating power supply is employed. The power supply
operates at an ultrasonic frequency and provides a 30-volt split supply to power
the circuitry involved.
The PA-II©incorporates a double-sided fiberglass epoxy circuit board to help
keep the size to a minimum, to insure years of trouble free operation, and to
allow us to build a preamp equalizer with incredible bandwidth without fear of
oscillations or noise.
The PA-II©has reverse polarity protection, and can be adjusted to accept input
levels from 150mV to 5V while providing up to 5V of line level output. The
dynamic capability of your source is greatly affected by the loading effect
presented by the input impedance of an amplifier. The input and output
impedances of the PA-II©were carefully chosen to optimize the transfer of
information from source to amplifier without sonic degradation. The load is taken
off of your source and placed on the very strong output buffer preamp in the PA-
II©. The four bands of equalization were carefully chosen to provide help in the
regions of a car audio system that most often have problems.
The low bass area is the most troublesome in most installations. Even the best
low frequency speakers being used in the mobile environment tend to roll off too
soon, leaving a void at the low end of the spectrum. The Sub Bass control on the
PA-II©is centered at 45 Hertz, providing the ability to boost the real low
frequency information missing most often.
The Mid Bass control is fixed at 180 Hertz, and provides a chance for the
removal of some of the extra information built up by the natural resonance of the
average vehicle.
The Midrange control follows a curve that matches the response characteristics
of the human ear. This allows the system's overall sound balance to be set to
where it sounds natural.
The High frequency control is set at 16 Kilohertz. This gives you the ability to
bring up the output of the tweeters at a point where most are rolling off.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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INSTRUCTIONS
Read the following instructions through completely. If they appear too
complicated we recommend you have an authorized LINEAR POWER™ Dealer
do the install.
GROUND:
The black negative ground wire should be connected to a solid ground point via a
bolt or self-tapping screw. This connection should be to a clean unpainted metal
surface.
POWER:
Since the current requirement of the PA-II©is only 150 milliamps, the red wire
can usually be connected to the power antenna or amp turn-on lead provided by
your deck. The red wire should not be connected to the source of constant power
as this would eventually drain the vehicle's battery. An alternate source of +12
Volts would be from an accessory toggle switch, which was connected to a
power source. This lead should be fused at 1 amp. (Use an AGC 1A fuse)
12 VOLT OUTPUT:
The red and white wire is an amplifier turn on lead and has 12V present on it
when the PA-II©gain control is rotated from the off position. Max. load current
from this lead is 300mA.
INPUTS:
The RCA (Phono) jacks will accommodate either high or low level signals,
ranging from 150mV to 5 volts. For low-level signals, always use shielded cable
and avoid routing signal cables in the vicinity of any power wires. The center pin
of the RCA plug is always the positive input connection.
OUTPUTS:
In a single amplifier system (no fader used) these jacks are used for sending
signal to the input jacks of your amplifier. In a two-amplifier system, where fading
capability is desired, use the FADER instructions found on the following page.
FADER:
The Patch back Fader is not operable until the signal is routed back into the
FADER INPUT. To enable the patch back fader, run a set of RCA cables from
the OUTPUT jacks to the FADER INPUT jacks. Then run a set of cables from the
FRONT outputs to your front amplifier, and run a set of cables from the REAR
outputs to your rear amplifier.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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ADJUSTMENT:
As shipped from the factory, the PA-II©is set for the lowest sensitivity. This will
allow it to match the speaker level output of a standard deck. In order for the
input of the PA-II©to match up to a lower level signal, the input level controls
must be set. These are accessible through holes on the rear panel, and can be
turned with a small flat blade screwdriver. There is a separate control for the left
and right channels.
Set the volume control on the source to maximum clean output.
Set the Gain control on the front on the PA-II©to minimum.
Set all equalizer controls on the center position.
Rotate the input gain controls clockwise until the clip light just starts to flash.
The PA-II©is now matched to the output of your source.
CONNECTOR LAYOUT
With the rear of the PA-II©facing you, and the unit right side up, the connections
are as follows:
INPUT, (Left and Right); REAR output, (Left and Right); FADER INPUT, (Left
and Right); FRONT output, (Left and Right); OUTPUT, (Left and Right).
GENERAL TROUBLESHOOTING
NO SOUND
Check all connections. Check fuses. With a meter to be sure there is +12 volts on
the main power wire, but not on the ground wire. Check all signal connections to
insure that they are properly configured and that there are no shorts to ground.
Check by substitution or other method for proper operation of music source.
Check that the PA-II©has been turned on.
BLOWS FUSE
Check all connections to be sure all power wires do not touch ground or each
other. Re-check polarity of main power wires.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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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.
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Specifications
PA II©
Output level *(max output level 7 Volts RMS) 0 – 5 Volts Nom.
Input Impedance 150K Ohms
THD @ full output 20-20KHz .01%
Signal to Noise Ratio >90 dB
Frequency Response 3 Hz to 75 KHz
Gain (output) Up to 32 dB
Channel separation >70dB
Current Draw 100 mA
Fuse rating .5A
Dimensions .875”x6”x3.875”
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© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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