The ST-10S (silver and black. i dont have/want a proper amp at the moment) is in my cart right now! Is there an advantage to the ST-10 vs the ST-10s?
The ST10S has a Black Gold and Black Silver version. They are differently tuned and have different impedances (ST10S Black Silver is easier to drive). So depends which ST10S u are referring to. I don't have the Black Silver one, but a few here who had both mentioned the Black Gold is better.
I have the ST10 (original) and the ST10S Black Gold, the Black Gold is superior when amped, but there's of course diminishing returns in this hobby. In terms of technicalities and subbass extension and tonality, the Black Gold is better. I found the original ST10 to be a bit cold in the mids and poorer in timbre. ST10S Black Gold can be almost basshead when amped in the subbass, and it has a less peaky upper mids/treble.
The ST10 (original) has better soundstage though, and is easier to drive. U really need an amp to drive the Black Gold, it sounds meh from a low powered source, so that's something to bear in mind since u don't want an amp as per your OP.