INTRODUCTION

Power Supply: Self oscillating for reliability and efficiency. The transformer is epoxy dipped for extreme vibration resistance. Banks of high speed TO-3 switching transistors provide massive current reserves.

Output Stages: Transformerless, direct coupled and fully complimentary. Output transistors are high current and low distortion TO-3 devices, operating at a fraction of their limitations.

Protection: Our stable amplifier design is made virtually indestructible by three protection circuits. One is a precision thermal protection circuit which prevents damage from high frequency oscillation, or an excessive ambient temperature. The second protection circuit is a current sensing device guarding against instantaneous abnormalities, such as short circuits. Both of these circuits automatically reset. The third form of protection guards against component damage from reversed power connections.

Construction Features: Our unique, 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 transformer and chassis, 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 this rigorous test have truly earned the LINEAR POWER logo.

Read the following instructions through completely. If they appear to complicated we recommend you have an authorized LINEAR POWER dealer do the work.

1. The amplifier works best if it is kept as cool as possible. Mount in a position that allows air to flow freely through the fins. Be sure there is ample space above the amplifier to avoid trapping heated air rising from the amplifier. The amplifier should not be mounted upside down. Avoid mounting any amplifier in the dash or on the firewall to avoid noises being radiated directly onto the case.

2. Mount the amplifier in a position that allows ample room for gain adjustments, and the installation, removal and attachment of 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.

1. Disconnect the negative ground cable from your vehicle's battery before making any power connections to your amplifier.

2. Connect the black negative power wires from the amp to a solid frame member via a bolt or self-tapping screw. This connection must be to a clean, unpainted surface. Always attach the ground wire first when installing this amplifier, and disconnect the ground last when removing this amp from the system.

3. Two fuses of the proper size must be installed in line with the main power in order to prevent damage to your wiring. They should be connected to the battery's positive terminal, or as close to the battery as possible. Use the fuseholders and fuses provided, and replace only with the same size fuses. The Model 1752 uses two AGC 30 fuses.
WARNING: USE OF OVERSIZE FUSES WILL DAMAGE YOUR AMPLIFIER

4. The other end of the fuseholders should be connected to the positive power wire from the amplifier. To extend the length of the power lead, use two 12 gauge wires or larger to reduce power loss. A single 8 guage or larger wire may be substituted, but don't use smaller wires.

5. The red and white wire 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 antenna lead exists, a source of 12 volts connected through a toggle switch will do. Do not connect the red and white wire directly to a source that will leave the amplifier permanently on as this will drain the battery.

6. The RCA (Phono) jacks will accommodate either high or low level signals, ranging from 200 mV 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.

7. As shipped from the factory, the Model 1752 will be set up as a normal stereo amplifier, and ready for a 4 ohm load on each channel. If you wich to engage one of the optional functions of this amplifier, remove the main power fuses to avoid the risk of electrical shock from the high voltage present inside the case of the amp, then remove the bottom cover.

Locate the switch mounted on the printed circuit board near the speaker connector marked: "Stereo/Bridged." Move to "Bridged" position. The left positive speaker wire is now the + speaker output, with the right positive speaker wire becoming the - speaker output. The two negative speaker outputs will not be used. Using only the left input jack, the amplifier will now operate as a bridged mono amplifier.

Unplug the two jumper wires near the four large filter capacitors from the lugs marked 4 ohm and press them firmly back onto lugs marked 2 ohm. This will allow the amplifier to operate into a 2 ohm load on each channel, or a 4 ohm load when used in bridged mono mode.

The output current capability of the 1752 exceeds the rating of standard speaker plugs. To ensure a good connection with this much power, a terminal strip is used. The speaker cable can be brought directly to the amplifier and connected as: LEFT (-); LEFT (+); RIGHT (+); RIGHT (-).

For any syatem to operate at minumum distortion with minumum noise and still reach full power output, the equipment should be aligned to operate at the same point on the distortion curve at the same time. In a basic system, using a single amplifier, set the amp sensitivity adjustment to minumum, turn the deck up until it just starts to distort, then back down slightly. This is the point where the output of the deck is cleanest. Now, bring the sensitivity control of the amp up until it just starts to distort, and back it down slightly. This will allow the amp and the deck to reach maximum usable output at the same time.

NO SOUND
Check all connections. Check main power fuses. Check accessory fuse. With a trouble light or meter, be sure +12v is present at the amplifier on the power wires and the 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 power wires and speaker wires do not touch each othe or ground. Re-check polarity of main power wires. Check impedance of speaker loads and setting of the internal power taps to insure proper match.

SHUTS OFF
As this amplifier is equipped with thermal and short circuit shut-down electronics, in the event of high ambient temperature or improper speaker impedances, the amp will turn itself off. To avoid damage to speakers, turn down the volume while waiting for the amp to turn itself back on. If this occurs repeatedly, use a fan to cool the amplifier and check for proper speaker loads and connections.