Radio Shack Optimus CD-3400 portable CD player Letters

A letter in response wondered about the "knocking"

Can you hear me knocking?

Editor: It blows my mind that all of you talented people missed a major screw-up on the Radio Shack CD-3400 CD player.

If you play it through the headphone jack, you will notice a double clicking sound in the right channel during quiet passages. I would have let this go, attributing the fault to my falling asleep with the $9 "special" Radio Shack headphones in my ears and pulling the damn machine off my nightstand about a dozen times. Lo and behold, my buddy, (world-, or at least Bay Area-, renowned) audio critic Sandy B., told me last week, without prompting, that he had heard this clicking on not one, but two of the now-famous 3400s, which he had bought and soon returned to the Radio Shack palace. Sandy believes that it could be a circuit or something in the jack that's picking up the spinning of the CD.

Three machines, three clicking noises in the right channel of the headphone jack. Help me with the math, fellas!?!—Neil Kallins, Greenbrae, CA

The clicking noise only happens when the batteries start to run low; it also doesn't occur through the line-out jack. Incidentally, a tip from Internet contributor Brad Sanders, as posted on The Audiophile Network: the CD-3400's sound improves when its display is backlit. This is because the four LEDs that illuminate the LCD result in a constant high-current draw on the same voltage regulator that powers the audio circuitry, keeping the impedance of its series-pass transistor low.John Atkinson

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