[WEEZ]

I only ask because most of the tubed pre-amps in a price range similar to your X-1 are single ended...and don't know your price range and/or whether you felt strongly about balanced or not...and with the relatively low input z of the X-250..it would be taking a stab in the dark to make a recommendation.

 

WEEZ

[PaulFolbrecht]

You would be wise to look into the Supratek line as well as the Dodd battery unit.

[CSI]

Always hard to predict how a component will change a system but don't overlook the PrimaLuna ProLogue Three. Probably the most underrated piece in the PL line. Not expensive and there are some better choices at higher prices but if what you want is added sweetness and warmth at the top end, this will do it. It does that in my system without taking away detail or making things too soft.

[Paul_Bui]

And don't forget the front-ends (transport/DAC), digital links, ICs and speaker cables will play a role in shaping the ultimate sound coming out from your speakers.  Let alone the room.  Did you mention what sources are you using with Pass Labs gear?

I once blamed the all silver ICs, digital link and [solid] silver speaker cables for the tendency toward sterility sometimes heard from my system.  After adding a tube pre (and a battery DAC) to the chain, I gained more of a fuller, sweeter, more extended more dynamic more "slam" quicker sound and lost nothing but a fraction of my savings.

Speaking of buffers, have you heard of Burson HDAM?

[Imperial]

Say... how about using a tube poweramp?

A Wolcott should do very well! (Say the new 280S will kick ass nicely!!)
Tubes would be like this:

- input tubes: 60s Mullard ( Phillips,  delta branded) E188CC
- drivertubes: 60s Telefunken ECC86
- powertubes: Mullard El 34 Xf2 dual getter from the years 1964-1967.
(setup is foretold by Porter)
Don't deviate!!! This iz da bomb on this amp!!!
And this will be a LOT better then a X250... on a Summit!!