Thanks for the replies. And I feel your pain overtime...
I'm wondering if it would be a worthwhile improvement over the internal DAC in a Squeezebox 3 playing mostly flac files into an aging but decent setup of homebrew pre-amp, Rotel RB991 power amps, B&W 603s2 and REL storm 3 sub... The SB3 sounds very good - not as good to my ears as my CD but the convenience wins every time.
At circa £120 (?) it might be worth a punt. Alternatively there is the DEQ2496 that can do room correction...