The 845 SET powering the Zu FRD in any configuration is synergistic; a perfect fit. One of my systems has Audion 845 Black Shadow monoblocks powering Zu Definition 2, and I sometimes switch the 300B PSET monoblocks I run into Druid Mk 4-08 with the 845s. It's always a strong combination, dynamically vigorous, tonally rich, strong bottom end, meaty attack; beautiful yet unretiring.
Phil
Phil