Which preamp to go with pass labs x150.8

You should be fine with ARC or XP-12.

As a general rule, the preamps are designed to go with the amps, but if you have the opportunity to try other brands, I’m a lover of the ARC sound, so I too would recommend the 28se.

Let is know what you decide.

depends what type of sonic signature you are seeking... everyone's 'best' is different

Audio Research. I have owned Pass amps for forty years and Pass preamps. The best mix to me (assuming you can;t afford an ARC amp) is an Audio Research preamp with Pass amp. I owned a Pass x350 for nearly 15 years.

Audio research old model amplifier is not expensive compared with pass amplifier.

I do not suggest a tube preamp with any SS amplifier,as it is not a good match.