With the amazingly good sounding Schiit Freya (had mine in the rig about 4 months) there is a gigantic difference between the very similar sounding passive and FET settings and the tube stage. Not only a huge gain difference with the tube stage, but a sensitivity to tube rolling that I find to be telling and a revealing tube rollers playground. I’ve settled on new issue Tung Sol 6SN7GTBs in the output stage, and NOS Sylvania "chrome domes" in the allegedly more important input stage. More tube options to come (fun...it’s fun) as 6SN7s can be found relatively cheaply, including "Bad Boys," NOS RCAs, and a perhaps a Northern Electric or two (large and sort of pricey). It’s interesting that anyone would find that Freya and Saga owners would find "no difference" between stages, as there is a mountain of banter online about these preamps that can keep you scratching yer head for hours.