Woodhart, that doesn't sound quite right, so I looked it up on Schiit's fact page, and they say this:
Freya+’s all-new tube stage with new-production 6SN7 tubes, DC heaters and semi-circlotron, noise-cancelling output stage is whisper-silent. Better yet, it turns off when you’re not using it! That’s right, both the tube heater and high voltage rails go away when not in use, so you can preserve lifetime of costly tubes.
They did this so the tubes life can be extended, so perhaps they didn't understand your question? BTW, I've got the Freya+ too, and the tubes are completely cool when not in the circuit. It's a great sounding pre, btw, the SNR and crosstalk numbers set it apart from many other tube pre's.