I use two of these into a midpriced DAC with a AKM 4490 chip set that feeds my main 2 channel system. One is for TV optical out. A tremendous improvement in show/movie watching. Now the soundcape is wide and deep. Deep bass is tighter, quicker and precise. The other is for optical out from an Apple Express when I Airplay music from my phone or Mac. The difference here is more clarity. Band members and intruments stand out better, even as far as hearing a background voice I never heard before. I recommend these gadgets to anyone unable to shell out thousands for an upper tier DAC.