Audiovox Wired FM Modulator Whines
Just installed my second Audiovox FMM100A wired FM modulator. The first
one had a high-frequency "whine" (like a carrier tone, but audible)
even with no audio source feeding the box and with the car engine shut
off. It's like taking a hearing test at the doctor's office with very
high-pitched tones. Audiovox tech support said that shouldn't happen
(the most dangerous words in technology: "it *should* work" followed
closely by "that shouldn't happen") and advised me to return it. The
second unit performs identically. It's not that I'm overly sensitive to
high freqs; the rest of my family hears it, too.
I've tried relocating the ground, feeding power from a separate
battery, wrapping the loose wires separately, enclosing the whole
package in foil and connecting that to ground with a capacitor to
intercept stray RF, etc.
The whine isn't as audible while driving, but it's loud enough to be
annoying even with the car radio treble turned down a bit. Otherwise it
works like a charm: when switched on, it routes the audio through the
car speakers on one of two FM frequencies even if there's a strong
station on that freq.
Anyone else have this problem? And/or a fix?
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