So on the Bartok, can you use both types of outputs at the same time? Actually what I want to do is RCA to a pre-amp and XLR to a headphone amp (or perhaps the other way around).
According to the Manual, Page 11.
The Bartók DAC has independent balanced and unbalanced line output stages, you can connect them to different amplifiers if you wish.
Presumably - at the same time -
Well I’d only use one at any one time. So if SWMBO wants to watch the telly or is complaining she doesn’t like the album I’m playing then I’d use the headphone amp. Other times it would be the speakers via the RCA outputs.
The outputs are independently buffered so there’s no issue with having a different load connected to the XLR and RCA outputs. We see this setup often and in some cases it’s as you describe and in others both are used simultaneously (e.g. to drive the main system as well as a whole-home system).
That’s excellent news.