No buzzing here as yet. When doing several consecutive evenings of serious listening, I leave the tubes on overnight with output turned low, then muted, with only FM radio as source. On rising next day, quiet background, no buzzing notable, even if I put in hearing aids (which have become indispensable for music listening to my old concert-battered ears).
I am running balanced in from DAC and out to amp, but doubt that would explain absence of buzzing. Not hard to find out, though. First swap the tubes, and if that doesn't help, it's never a bad idea moving to XLR if your input/output components support it.
BTW, my view of the Freya+ is like @alymere's; A perfect rest stop enroute to a "definitive" contemporary tube preamp-centered system, and now becoming the weak link in my chain as other components have been upgraded.