Well, this isn't really a review as it is more like preliminary impressions. I'm listening to the Ref1 with stock cable comparing the ZX1, AK240 & CLAS -dB/Duet set. Although the ZX1 plays well with the Ref1, I feel I enjoy it more with the AK240 or CLAS -dB/Duet in the sense that those two are able to leverage on the Ref1 bass capabilities more fulfillingly. I think I like the ZX1 more with IEMs such as the FitEars but for something like the Ref1, I'd like a neutral to warm/neutral-styled DAPs. Maybe I should whip out my HM-901 to try pairing it with the Ref1.