Tube preamp for Pass Labs amp

Audiofeil, I'll bow to your experience, but the Pass amps appear to be less than ideal candidates for many tube pres, when one considers the the low input impedance and the preference for balanced inputs. Both of which would seem to disqualify many more tube than ss candidates. Perhaps you'd like to share more with us?

Atmasphere, I know some pres have the the prerequisites, but it seems as though there are a lot more tube single ended pres with high output impedance's than ss ones. The Pass amps are particularly low input impedance, and the design seems to be particularly built around maximizing the use of balanced inputs.