Does a tube preamp warm up sound of SS amp?

I posted on your power conditioner Q.
Yes a tube preamp can warm up a ss amp. If you want a lot of the tube warmth, Conrad Johnson is great (though CJ is singlle ended only). If you really want a not-too-tubey sound using tubes, later models Audio Research (ARC) is the ticket most are Balanced output) . Both are great companies with good service. BAT is another good brand of tube stuff.
Most other tube preamps are smaller companies (some folks like that, I do not)
ARC does not sacrific clarity for tubeyness. (I am big on clarity, and like the Bryston BP-26 for that reason)

The Bryston has a lowish input impedance on its XLR inputs, 20K Ohm per phase (it's common to give the sum of the phases in spec sheets), making it a poor match for some tube pre-amps with high output impedances.

The single-ended input of the Bryston is 50K Ohm, which will work with more pre-amps, but I'd still avoid very high source impedances (say 1000 Ohm and above).

If you want more flexibility, I'd look for an amp with a higher input impedance like 100K Ohm.

Thanks for both comments. Very helpful. The Audio Research ls5 mkii has Input impedance of 200K ohms balanced and Output impedance 400 ohms balanced Main (2), 20K ohms minimum load and 2000pF maximum capacitance. From what I think you're saying that ARC could work, right? Laurence