How did the Gustard X18 and the D90xE (x=L,S) compare soundwise, as they seem to have quite some things in common? Compared to the DX7 Pro I currently have, I like the sonic improvements of the D90xE. Wonder if this would be true for the X18 as well.
This is subjective, as I could not test both dacs at the same time.
But, with the Gustard X18, I had the impression to find the sound of the D90SE/LE...unlike SMSL SU9N.
Note one point about Gustard x18. Under linux, DSD drivers are a problem, in my opinion they are generic, but they will eventually arrive. When switching from a 16/44 track to a DSD track (only in this case, 24/44, 24/96, 24/192 etc...to DSD works), there are crackles for about 10 seconds at the beginning of the track. I decided to switch back to windows and I no longer have this problem.
A friend also bought the Gustard X18. He absolutely wants to stay under linux, to get around the problem, he samples the 16/44.1 in 88.2. And it works perfectly.
Apart from that, I highly recommend it.