Digital Clock Noise

I have a 1999 Panasonic DVD/CD H1000 that has developed strange noise in the left channel only. I have tried the player in two different systems and with different interconnects. The noise is subtle and can only be heard in the quieter passages of the music - but it IS there.

I would describe it as being somewhat like a tree full of little birds tweeting and chirping way off in the background somewhere - perhaps with some other "electronic" sounds added to the mix?

Is this digital clock noise? What might be causing it? Can it be fixed by a professional technician for a few hundred dollars?