Homebrew Condenser Microphone
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| Well homebrew might be a bit misleading. This is obviously a Shure ball mike. I found this mike at a flea market for a few bucks. The cartridge was bad so I discarded it and replaced it with a condenser mike element. This is a model 270-090 cartridge available from the local Radio Shack store for $2.49. The circuit (figure 1) is very simple. The key to getting satisfactory sound from this element is to use a smaller coupling capacitor than the one recommended by the manufacturer. Use a .005 cap. The original value of 15 uFd produces very bassy and muddy audio. The parts are mounted on a small piece of perf board that I cut out to slide into the rubber gasket that once fit around the old mike cartridge. Pin 1 is ground, Pin 2 is +4 volts (supplied by the transciever) and Pin 3 is audio output. |
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Figure #1
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| I use my homebrew consenser mike with my Ten-Tec Jupiter. The Jupiter supplies +4 volts at the mike connector to power the condenser element. |
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