Building a Faunette:
Noise Filter (Modified Audio Cable)

Although this filter provides sound to two speakers, it is actually mono doubled, not stereo. If you have a stereo TV/VCR, this filter will work, but both speakers will play the left channel. You can order (or build) a stereo noise filter, but it may cost a few dollars more. Remember: The noise filter does not reduce all the buzzing. See Computer Speakers in the Technology Components section for additional information.

To assemble the noise filter, you will need to purchase the following parts at any Radio Shack.

1. #274-375B. Y-Adapter splits stereo mini-⅛ circuit into 2 mono ⅛ circuits.
2. #42-2158A. Y-Adapter Microphone Cable for connections between single microphone and dual microphone input jacks, and ⅛-inch phone jack to ⅛-inch phone plugs.
3. #274-286. Mono Phone Plug (2). Fits ⅛-inch mono phone jack. Solder-type terminals. Screw on housing.
4. #273-1374. Audio Isolation Transformer. 1:1 turns ratio.
5. #274-1555C. ⅛-Inch Mini Jack Coupler for mono-to-mono or stereo-to-stereo use.
6. #42-2420A. Six-foot, shielded audio cable for connecting audio components, ⅛-inch mono to ⅛-inch mono mini-plug.
7. #274-372A. ⅛-Inch Right Angle Adapter for mono-to-mono or stereo-to-stereo use.
8. #278-1627A. Heat-shrink tubing. Variety pack.
9. Soldering pen and electrical solder.
10. Electrical tape (black).

Assembly

The parts are listed in their order of assembly: steps 1 through 7. Parts 8 though 10 are used to secure the components. The whole filter can be assembled by snapping parts together in order, except for #4, the audio isolation transformer. Four wires have to be soldered to the solder terminals on #3 (the two mono phone plugs).

The black and red wires of #3 are the same circuit. The yellow and white are on the other. Solder the black wire onto the bottom (or long piece) of one of the mini-phone plugs. On the same one, solder the white wire to the middle (or shorter piece) terminal.

On the other mini-phone plug, solder the red wire to the same spot you soldered the black wire and likewise the yellow wire to the same spot you soldered the white.

The solder points have holes where you can stick the exposed wires of the audio isolation transformer. By twisting the wire in and around the holes, you can secure the wire while you solder.

Place the two mini-phone plugs back-to-back where the wires come out of each. Cut a piece of heat-shrink tubing just shorter than the length of the two plugs. Don’t cut it so long that it covers the silver electrical connections. Slip the tubing over the connectors, keeping the audio isolation transformer out of the tubing. Squeeze the plugs together so there is no room between them. Using a lighter or match, heat shrink the tubing around the plugs by moving the flame underneath, back and forth and all around the tubing. The tubing will shrink tight around the plugs, holding them together.

Use electrical tape to secure the wires around the connected plugs. After the wires are taped down well, tape the audio isolation transformer around the plugs as well. The idea is to keep the wires from pulling free of their soldering points and to secure the audio isolation transformer tightly to this “sound filter” cable.

The right angle end of the filter goes into the earphone jack of your TV. The other end plugs into your computer speaker’s audio input. Now you can reduce that annoying buzz!

If you use a car stereo amplifier and speakers (see Alternative Sound Amplification), you can make a quick modification to this sound filter. Replace part #7 with two of Radio Shack part #274-871 (Adapts ⅛-inch mono plug to fit phono RCA jack).

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