Hi Simon,
I use Quad 11L and 12L's in my AV system and have briefly tried them in place of my Vandies in my hifi system which has a Caimanized 7520. The Caiman will improve overall quality without a shadow of a doubt and produces a valve-like warm sound. It can, of course, be further tailored by changing op-amps if the sound isnt exactly what you want.
Jerry
Hifi: IPL transmission line floorstanding speakers, Squeezebox Touch, Denafrips Ares 11 DAC, DCB1 Pre-amplifier, Croft Series 7 power amp.
Custom Hifi cables HA10SE headphone amplifier and Hifiman HE-400 headphones.
AV system: LG 55B7, Denon AVR -x2300w receiver, Quad 12L (front) 11c Centre and 11L rear . Velodyne DD15 subwoofer.