I was looking at some of the pictures of the various boards mounted in the Bartok and was curious if this was of the headphone variety or not? Is that vertical card mounted to the front of the unit the headphone preamp or is that elsewhere in the box?
This photo is of the headphone variety.
The headphone variety of the Bartók has this dedicated transformer (front at the bottom):
From this side shot (left side) you see the blue, yellow and white power leads leave from the dedicated transformer towards the front board you indicated:
This internal shot is from a Bartók without headphone amp (front at the top). The above transformer and the front board are not there: