I've updated my most popular Mac App Store application : Optical Audio Port Keepalive.
Let its description speak for the app :
"Do you use an optical audio cable to connect your mac and your amplifier? Do you experience one second silences in high fidelity music, lost words and lost sounds in movies? Well, it's not your nor your hardware's fault - it's an energy saving feature of the optical audio interface - the S/PDIF standard. And Optical Audio Port Keepalive is the solution for you!!!
OAPKA generates an absolutely unhearable tone that prevents your optical audio output to shut down at short silences/musical breaks, so you can enjoy an uninterrupted hi-fi audio stream. Enjoy!"
I changed its name and its UX - it is now a menu bar application. And I have also released its source to the public domain :