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For my last birthday, I got a Panasonic cordless phone. The base has a radio with digital tuning and an analog volume knob.
I keep it next to my bed, and listen to it while falling asleep. Nearly every night, after turning it on and adjusting the volume to a very low level, a few minutes later, the volume has lowered so that it can't be heard at all.
At first, I thought it was just changing to a quieter song. But surely sometimes a louder song would come on, right?
Is there an explanation here, or is my apartment haunted?
Mac
Those kinds of radios most likely use op-amps, which are integrated circuits (IC's). The configuration of these amps is usually such that a portion of the output from the output is fed back to the input (out of phase) to cancel the input (known as feedback).. What's likely happening is that as the IC and other components warm or cool slightly (either as it starts to work, or due to being snug beside you in bed) the properties of the components change ever so slightly.
This very slight change in property can contribute to change in the feedback chain, which in turn causes either a negative of positive gain increase (a negative gain in this case, it depends on the phasing & type of amp [inverting or non-inverting]).
In some cases if the circuit is poorly designed, it can "run away" i.e. the change in amplification causes another change in the circuit which in turn causes another effect on amplification and so on and so forth until the output is either increased to maximum or decrease to 0 (or close to it).
If this is the cause, then there ain't anything you can do about it...
It just occured to me that another reason might be that your volume control is rubbing against the pillow or something and turning it down - lol :)
rubbing against the pillow
I had a problem with my car that was almost that dumb. The floor mat kept getting pushed up and jammed under the gas pedal. I couldn't figure out why the acceleration was sluggish. :)
