I'm running the standalone ST. The STL is only MPX capable. I'll try the ST in winamp later, but why should that make such a difference?
The "heli" sound of RDS is barely noticable to the common ear, I'm just pushing my self to hear what's underneath the music or between songs. Maybe it's a detail which can be noticed only by people in the broadcast industry/radio freaks!
I can hear the RDS sound on an FM receiver, I haven't tried listen directly the soundcard's output.
Btw, I should also inform you for my studio setup. There is a computer running the radio automation software, giving audio to a mixing console, then master out of the console is going in to ST and then the ST output goes to the STL. I've already checked the mixing console for unwanted signals, swaped it with some others but I get the same thing. I've tried different cards at the automation PC, same thing.
About the STL: I don't think that there is a problem in that, since I get correct results when I use the AEV Stargate stereo coder+RDS and I leave ST to do the sound processing job.
Since this is a commercial station, you all understand that tests cannot be done all the time, so I can try things only during at night.