I was an early adopter of a Schiit Freya preamp...the original version that doesn’t turn the tubes off when switching to "passive" or "FET" modes. You want to hear how much the tube mode distorts or at least hear what sounds different from passive? Instantly find out with your remote...I do it all the time just to see if my insanely long lasting old stock GE 6SN7GTB tubes are still happy...since the tubes are always on, this switching of modes is too easy (be on the fader as the gain in the tube stage is much hotter) and always rewarding. New Freyas need some time for the tubes to warm up so it’s somewhat less instantaneous but doable anyway. Some actually prefer the FET or passive mode, but I assume they haven’t tried tubes other than those originally supplied or, surprise surprise, they have tastes that differ from mine. My Freya sounds amazingly excellent and utterly musical in any of the 3 modes, and since it’s a brilliant design for less than a brake job, I very highly recommend these things...it’s rated superb by me and Class A by Stereophile. What’s not to like? My Pass XA-25 has been a perfect match with the Freya, but that’s another story...with a happy ending.
Preamps can color sound considerably. Surprising?
Had the pleasure of listening to 4 hi end preamplifiers this weekend. And each preamp sounded very nice. But they were different. Each preamplifier has different circuitry and within the frequency spectrum there was more vibrancy in some areas versus other areas. Amplifiers are the same way.
It takes a while to appreciate sound differences between preamplifiers. And then you got the issue of Breakin which further changes the color.
clearly designers are playing around with all the internal circuitry in a manner that hopefully will be appealing. Clearly, these units do not get out of the way when it comes to moving a signal through the box.
I think solid state is more susceptible to coloring versus tubes. Tubes color sound as well.
It's all about marketing different ways to color Music. This isn't necessarily bad but it's never really talked about this way.