Preamp for Pass X350.

i need a preamp (tube/ss) for my x350.
if anybody listened this combo and enjoyed,i'll happy
to know.
I have an X150 and have had excellent results with the Placette. And you should certainly consider the PAss pre-amp. Wth tubes, be mindful that the output impedence of the pre-amp should be 1/10th or less the input impedence of the X-350, which is probably around 22K (on the low side for amplifiers).
Match it up with any of the Nelson Pass preamps, even going back to his Threshold days. Pass X-0, Threshold Fet 10E are two of his best preamp designs. Also, a Threshold T-2 balance preamp is excellent synerygy even though it's not a Nelson Pass design.
I heard an X350 driven by a Pass pre and was VERY impressed. It now as me thinking about an upgrade. (please wife don't hit me ... I won't say THAT 'U' word again)