Input Jacks

able fur $L80 from Motorola, 4910 W. Flour-uey, Chicago, Illinois, and dresses the amplifier up. The only draw-back with this is that a large hole has to be cut out of the panel and may present a problem to someone that hasn't access to the proper tools for this job. Ail alienate method is tu drill a series of holes in I he panel to pass the sound from the speaker.

The module and power supply were built on a piece of 3% x 3;* glass epoxy board that was handy, but a piece ol perforated phenolic will work as well- Phis chassis is mounted behind the speaker by threaded bushings and secures the grill, speaker and chassis in a neat sandwich configuration. ! he mounting of the components is not critical; the only precaution is to keep the power transformer away from the amplifier module to keep hum from being induced into it.

After the wiring is completed be sure tu check all connections for proper solder and lead dress. If all checks out then the unit can be connected to the line. When the unit is turned on a slight hum will be heard from the speaker and when a finger is touched to an input, a harsh buzz should be obtained. Now connect an audio device such as an audio oscillator or AM-FM timer to the input. It should he heard with plenty of volume. Only one precaution must be observed and that is that no more than 400 volts DC can be connected to the input. This is determined by the voltage breakdown of C3.

Your audio test amplifier is now ready for many years of signal tracing, always ready the moment it is turned on.

Inside of the audio test amplifier



• Excellent 50 Ohm impedance match.

• One inch drawn 6061-T6 aluminum, tubing. Easy installation.

• Telescoping end sections allow for pin point resonance tuning from 1 4 MC to

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