Van Alstine pre-amplifiers

You need to get a flat frequency response in your room before chasing the tone and timber.

Amen. My guess is that 90% of the debates and discussions here are not controlling for the variable of the room. This assumption helps me sort through these fora much more effectively for useful advice. Otherwise, it's there's a lot of flatus vocis.

I've had my AVA FET VALVE CFR PREAMPLIFIER for a few months, but haven't really spent any quality time with it.   Having said that, I will say this:  It is a huge improvement over the Parasound P3 that it has replaced.  

Have you any preliminary impressions regarding its sonic character?

Van Alstine Transcendence RB 10 feeds a FirstWatt F8. No exaggeration of richness, and no defects, no brightness and no muddy bass. Just an excellent and accurate musicality.

I've had an AVA FET Valve CF preamp in my basement system for about 5 years and it's been paired with an AVA 600R hybrid power amp.  It responds well to tube rolling and I currently have 2 Mullard NOS 4024 (12AT7) and 2 Brimar NOS CV4003 (12AU7) that improve nearly all aspects of the SQ including tonality, soundstaging and imaging.  Also it's been absolutely trouble free during this time.