Problems with playing through DAC/headphones


Just bought a TEAC UD-501 DSD DAC and have been listening to lossless files via iTunes and DSD via the TEAC player. I am listening primarily through headphones, and the sound is great. For some reason, though, if I try to load a video via youtube or if I try to listen to music clip on an internet website, I hear nothing via the headphones. I have a MacBook Air and check the sound settings -- the TEAC is selected as the primary output, so I can't understand why I can hear music via iTunes and other dedicated players but not via my web browser. Any insight into this problem would be greatly appreciated! Thanks!
jawks
Checked all my settings, and everything seems set to play through TEAC. I wonder if, as you say, something resets or doesn't switch over appropriately, when I toggle between iTunes and Chrome or Firefox.
Funny thing is, when I was using a Nuforce ICON HD DAC with the same headphones, this problem never happened. I could listen to all sources on my computer with no problems without having to exit the programs. This must be unique to the TEAC.
With DoggieH. on that one. Do you have sound if you try to play a YouTube vid first and only? (no iTunes played previously during that session??). I do notice even trying to eject the external hard drive where I store my iTunes library that if I haven't QUIT both iTunes and BitPerfect the drive won't eject because one or both are still using it...this despite thinking I have stopped and exited iTunes and BitPerfect. Definitely worth trying to quit iTunes before switching to YouTube. Good luck.