I only tried it on SE with my 1Z and High Gain and I loved the pairing. In fact, I preferred the 1Z over LPG. I can't comment on the tonal synergy between the 1A and i4, but from a power requirement perspective, the Sony DAP should not have any problem driving the i4, especially on 4.4 BAL as I was only on 50/120 on the volume setting. But some users did comment that they felt that their Sony DAP was not powerful enough to drive the i4 even on 4.4mm. So it could depend on the volume level of your recordings as well as the volume level at which you listen to music. @flinkenick is using his 1Z to drive the i4 as well and he is liking it. If you are fine with using EQ, you could also ask him for his EQ setting and use it as a baseline and then adjust it per your preference.