Hi Ken,
Nonetheless, he started the thread inquiring about the Pass Labs X1. "Does Anyone Own the Pass Labs X1 preamp?"
Since you apparently do not, then plugging Spectral(twice) seems quite deviant from the initial inquiry. :-)
Having some experience with Pass Labs products, I would politely suggest that the X1, utilizing the Supersymmetric gain topology that Pass uses in their X power amps, offers a dynamic, transparent, and musical presentation. It has plenty of gain (sometimes too much for sensitive speakers), excellent instrument placement in the soundstage, and a lively characteristic that is quite faithful to the source information presented to it. Combining the Pass with the Krell would enhance the bottom end slam that K is known for, allowing also for excellent control of the lower registers. Plus, the X1 is airy enough and somewhat less analytical than the Krell preamps, so it might ease the Krell as would a tube without compromising dynamics, and certainly without any of the maintenance issues.
The Supersymmetric circuit topology that Pass uses effectively reduces noise and distortion by an order of magnitude compared to other such gain circuits. This allows for very fast transients and explosive peaks.
Cheers!
Quin
