Could you please share what "new level" was added to your sony zx1? My curiosity is piqued.
Although I bought it to drive my ipod , I tired connecting my ak240 line-out to the PHa-2 as an amp and I must say the amp adds more punch and dynamics to the internal amp of the ak240 when driving the mad dogs planar headphones. Differences were less obvious on iems as the ak240 has a mighty enough amp section for iems.
Now I can't wait to A/B the PHa-2 driving my iPod with my Chord Hugo at home, though I do suspect I know the winner already in this case.
Difficult to pinpoint the exact differences but I'll try.
If I use my Ety er4s with the amp section it gives a bit more volume but for me doesn't change the signature of the Zx1, which is no bad thing. However when I use the dac section it seems to add more volume power but also gives a smoother sound. Now this isnt to say that the ZX1 needs this as it sounds stellar without the PHA-2 esp with my AKG K3003 but the PHA-2 does seem to just add a little something very nice to the mix.
I wouldnt say it adds loads of extra bass or anything else amazing just kind off smooths everything and makes it sound a bit more amazing.
I know some would rather a more in depth description but I cant put into words the very subtle difference it makes.