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What does the Clipping Indicator Do?
Next is the clipping indicator, a frosted red LED that lights up every time the amp clips.
"Clipping" is what happens when the signal tries to get bigger than the power supply volt-
age, which it can't, and the peaks in the signal get "clipped" off. The result is a miserable
crackling sound.
But in the case of the BitHead, the clipping indicator not only tells you when you've got a hot
signal, it also tells you when your batteries are low. Because we're using some of those new
multi-voltage "rail-to-rail" interated circuit chips, the BitHead will run on a wide range of volt-
ages. And because "normal listening level" will vary widely due to the varying impedances
of headphones on the market, we can't really estimate how long the BitHead "should" run
on a set of batteries. (The battery voltage may lower to clipping after 20 hours of use with
a difficult-to-drive pair of AKGs, but you might get 60 or more hours of use at a comfortable
listening level when driving a pair of efficient Grados.) We realized that a clipping indicator
on the ever-diminishing voltage of a set of batteries would be the best low battery indicator of
all. For a given volume level at your headphones, the battery voltage will eventually get lower
than the signal, and the clipping indicator will start to blink with the louder bits of the music.
If the clipping indicator starts blinking more and more at your normal listening volume, it's a
sign that your batteries are on their way out and need to be changed soon.
An example of the input signal, and the output signal clipping
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