As the proud owner of a VAC Ren pre, I was flabergasted (astounded, amazed, etc) when I heard the Veloce LS1 battery powered tube preamp (about $14k or so). This is easily the single most dynamic, blackest background, most musical pre that I have ever heard in any system. Having taken one home for audition ( with the corresponding matching phono stage also battery powered), I am now in the process of trying to figure out how to pay for the one I have ordered.
