I was looking for an inexpensive set of 4 tubes to have on hand in the event one or more of the new Tung Sols that came with Freya start to exhibit problems. The best deal I could find were the NOS Russian tubes from Schiit, at $32 for a set of 4, so I pulled the trigger. Outside of Schiit, the least expensive I could find were around $15 each (I didn’t look on eBay). I enjoy Freya, and I think I started detecting some sonic differences between passive/JFET and tube gain. There’s nothing wrong with passive or JFET, but tube mode does add something extra - a bit more spaciousness, a more “open” sound (and I do volume match as best as I can with my Radio Shack SPL). I’ve never employed a pre-amp in my system prior to Freya, so I may just be a noob about all this, but I really enjoy what Freya brings to my system. I bought Freya for the convenience factor (centralized control) and volume control hoping it (she?) wouldn’t mess up the sound. Freya, as an unexpected benefit, seems to synergize quite well with my gear. I can’t get enough of listening to my music now - on speakers and on headphones. $799 well-spent, and another big win for Schiit (along with Gungnir Multibit and Vali 2) as far as I’m concerned. P.S. Still not being swayed by the siren call of tube rolling.