I am currently listening to the Quicksilver, (great preamp BTW), the Marsh b2000, also great, the Marantz AV8003, and Calypso. Recently auditioned ARC Ref 5 and 10, with my amp, and preferred the Calypso. The ARC preamps were superb, just a little less fleshed out. But, better separated and layered stage. Hard to fault, just taste preference. I also compared with the latest VTL, good but balanced a little warm...a beautiful warm though. Must match with your amp and cables.
The Calypso is just magical. Forgiving, yet revealing and accurate. A real keeper.