INSTALLING EQUALIZER JACK IN THE AC-300A

Installing an equalizer jack in your amplifier could reduce the resale value of your unit. Hilton Audio Products will not accept a unit that has been so modified.

Equalizer jacks may be installed for either or both the phono or microphone channel. When installing in the microphone channel, microphone 1 must be used. To install a microphone equalizer jack on some early AC-300As the microphone preamp board may have to be modified. If the mic preamp board has a resistor close and parallel to the edge that plugs into the main board, it will require modification. Please contact us for details.

Other than mounting the jack or jacks the wiring is very simple. The jack should be located near the volume control to keep the wire length as short as possible, reducing the chance of hum pickup.

REMOVING THE AMPLIFIER FROM THE CASE

Slide a screwdriver under the chrome handle cover and snap it off, exposing the two screws which hold the handle in place. Remove these screws. On the opposite side of the unit, locate the two rubber feet. Remove the screws that hold these two feet in place. Before removing the amplifier from the case take off the platter and set it off to the side. Also make sure the tone arm is locked in its clip. The entire unit will now slide out of the carrying case. Place the amplifier upside down on some padding with the controls toward you.

In order to mount the jack it will be necessary to remove the preamp. Drill a large hole (approx. 1/2" diam.) in the chassis, and a 3/8" jack mounting hole in the preamp. These holes must line up with each other. Drilling a small locator hole through both chassis panels, before disassembly, will help align them.

After mounting the jack, remove the black wire from the volume control and attach it to the tip connection of the jack. Refer to diagram below.

Connect a jumper wire from "X" to ring terminal on the jack.

Connect a wire from the ring connection on the jack to the lug on the volume control where the black wire was connected.

Connect a wire from the ground lug on the jack to the ground lug on the volume control (where the brown wire is attached).

EQUALIZER JACK

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