I agree that bypassing the iPod DAC is a significant improvement in sound quality. I have tried feeding the D12 with optical and USB from my Mac and was quite impressed with the sound but for some reason my most 'ohh yeah' moment has been when using the Algorythm solo. This then feeds the d12 an anologue signal but it has more top end air and detail than I have previously heard from the d12. For example I used to think that iems couldn't get close to the imaging of a good set of cans but since adding the CLAS that gap has closed significantly. And all this with just using cheap, but nice quality fiio interconnects. My Piccolino connects are due in a week. The D12 sounds really well balanced, fast and tight in it's current set up with the Hiflight opamp kit. How do other users find the D12 in sound quality compared to say a RSA 71b or Alo RX mk2?