I Will share some thoughts about the differences between SP1000ss vs SP1000cu, since I think it will differ from the general consensus:
For me...the SP1000ss is more soft or rounded in the highs, more rumble in the lows and neutral in the mids, not a warm tone, maybe a neutral/soft tone, all this in the balanced port.
The SP1000cu is more sharp in the highs a little more detailed here, less rumble in the bass and more prominent in the mids, it produces excellent perfomance in female voices, tone a bit mid centric with excellent highs and controlled lows, all this in the balanced port.
The tracks i used in this comparison are:
Barton Hollow -the civil wars (24bits/48khz)
The girl is mine and thriller -Michael Jackson (DSD)
Hotel California- Eagles (24bits/96khz)
In Twilight Hours - Kamelot (16bits/44,1khz)
The Headphones i used are:
Hifiman HE1000SE
64 Audio U18t
the differences are subtle but easy to hear...both players are in the last firmware (I don’t hear differences between firmwares)
It’s something wrong with both units?
I don’t think so, i own both so i can hear this for a large margin of time...
At least is funny to know that my opinion is almost the opposite to the general statement about the sound of both players...
Both are superb soundwise by the way