Hi, I've been reading a little about external USB DAC's and how they can really "upgrade your listening experience" . . . which sounds like marketing twaddle but hey ho. I listen to music sat at my desk in front of an old mid 2010 iMac. This is connected via an Optical TOS link to my, again old, Onkyo CR515 DAB system and a pair of Onkyo D-N9BX bookshelf speakers which sit on my desk, either side of my iMac. So I essentially sit around 1-2 feet from either speaker. The room is small, about 8 foot by 10 foot and the desk is situated in a corner (I've heard that all this stuff makes a difference). My music is a mixture of Apple Music streaming, 256bit AAC, Apple Lossless CD quality and a couple of albums of 24bit 96khz studio masters from Qobuz. I have done a few comparisons between these Studio Masters and the same tracks in 256bit AAC and the Studio Masters do sound a little better, fuller, more dynamic range but it's not a huge difference. Would my setup going to allow this difference to come through or should I not bother with Studio Masters unless I upgrade the Onkyo system or DAC or both? As far as needing an external USB DAC goes, I thought that using the Optical cable bypassed the DAC in the iMac and instead uses the DAC in the Onkyo system which is likely going to be better. I've been looking at the Audioquest Dragonfly, especially as a new version is due soon, can anyone recommend it or advise otherwise? I'm not sure that adding one to my setup would be any different to what I currently have and would like some people with more knowledge to help me clarify that I'm right or wrong.