Ok, here is the appropriate thread to post my 1Z mod. Thanks to
@Whitigir.
It's been very interesting couple days after found out the best possible wire for S-Master active ground. Changed from fw solis3.02 to U3.01.
Clearly, purest copper is just not good enough IMO. Good improvements overall but it darkens the background a bit too much. It's not bad. In some sense it's like listen to vinyl records. But it keep me thinking in my mind it's might not resolved enough.
Later I try silver plated and there goes all the nuance lower level details, airiness/spacious from upper mid which I missed is back. But treble might be over aggressive sometimes.
2x silver plated or silver plated + copper wires will improve soundstage and warmth overall but I feel like it lags some resolution and speed from the bass.
So now I think if I can apply the same technique from 4.4mm negative terminal mod on to this and the result is much better. 22awg OCC silver plated wires with 22awg 2mm length OCC. Solder them on each side. Here is what I have noticed so far. Treble is just prefect and extremely resolved. Sounds like real thing. Never too aggressive no matter what you throw at it. All the nuances, sparkling, airiness, and spacious in upper mid is so addictive to listen. Never thought it would possible for 1Z but there it is. Resolution is extended even more, dynamic is heavier fast, very detail soundstage 3D like, depth has more details, longer decays and go even fairer back. All that make everything much more fun, addictive and very satisfying. Classical, vocalist records are so warmth, emotional, and very romantic. Much clearer and better isolation between instruments and vocals separation. Lower mid Sony sound signature is all there and even better (Loose it if use single silver plated wire). Sub-bass is fast, heavy, extended, and slower decays.
It turns out just copper wire for battery will make everything a bit more vailed. Silver plated makes treble north from neutral. Mixed two type of wires together will take care of those peoblems.
After all that, it seem battery runtime is lower now by 15 maybe 20%. I think my 1Z is so resolves now even connect to charger I can hear a small improvement in SQ. Maybe now I have to turn off battery saving mode to get the most out of it.
