Pass X-250 and Tube Preamp

I am thinking about a Pass X-250. I noticed it has a very low input impedance. How do you think it would match with a tube preamp?
I'm running a McCormack DNA-500 (10kohm input Z) with a Dehavilland UltraVerve (600 ohm output Z), and the combination is terrific.

The impedances you are dealing with are probably in the same ballpark. If you stick to the 10 to 1 rule, i.e. the amp'z input Z should be at or greater than 10x the output Z of the preamp, you should be ok.
I'm very happy with Pass X-250 and ARC LS15 for the past year.
You can increase your odds of success* by keeping the interconnect cable short; 2m or less would be good. The lower the output impedance -- closer to 100 ohm than 500 ohm -- the better your chances are.

* avoiding loss of dynamics, truncation of frequency extremes, and loss of immediacy.

Best of luck,
I've never liked my speakers (thiel 2.3) with tubes. I currently loving and enjoying my pass labs x-350 and x-2 the synergy and musicality is awesome.

Try to find a tube preamp with balanced outs.
An inexpensive good tube preamp (true balanced, use XLR)that worked wonders for me was the Cary SLP-2002. Use 6CG7 gain tubes instead of the 6922's to reduce the gain to match the high gain output of the X250. I used to run this combo & liked it better than a Pass X2 pre w/the X250. There are many past threads on this subject you can reference too.
Get the 250 and then trade it in towards 250,5.Thats what i did.Cost -2000.
I posted on this a year or so ago. I owned the X-250 for a few years and compared a bunch of tube preamps to the X-1 preamp. Lamm LL2, Blue Circle B-3 MKII, ARC LS-25 MKII, Counterpoint SA-5000, Joule LA-150, BAT VK-30SE, and a few more that I cannot recall right now. That being said, they all worked just fine. I even tried a few passive preamps that also worked pretty well but there was a slight gain issue with these but not real bad unless you listen to music really really loud.

Happy Listening.
My preamp is not balanced. Does this change any of your opinions above?
A mate of mine has Herron tube pre amp with X350.5 running unbalalanced. No problems at all.
No not an issue the balanced cables offered a slightly blacker background and slightly better details but that could also be the cable design.

Happy Listening.
I had anX250, it sounded great with a ML No. 26 preamp BALANCED mode.

YOu can also try a First Sound preamp, it should work nicely.