What is the Goldmund sound?

Rich in detail, VERY extended highs and "authoritative" in the upper register (you don't feel that an it's going to lose it on an extended note). Favours clarity and detail over a lush presentation. I wouldn't call it analytical (that has negative connotations) -- rather, on the slightly coolish side of neutral. This said, it sounds very good on classical (IMO), so I haven't found Goldmund to be offputting or tiring. Overall, I like Goldmund a lot even though I do not now own any of their equipment. BTW, it's wide-bandwidth reproduction (as in Spectral, et alia).

I don't know Stellavox at all.

We were a Goldmund dealer for several years selling the current line of electronics. I found the lesser expensive equipment a bit shy on body and music. Goldmund claims to have "a sound" but it is vastly different at each price level. Listen before buying. Matching is very important.