jack,
i am not familiar w/the tuna oferings of ava. re: *my* personal faves, i am partial to a hot-rodded h/k citation 18 i have, and a rare onix bwd-1 w/outboard soap power supply. the onix is similar in design/ergonomics to the naim nat-01. w/these tunas, (and many other tuna i've tried), the sound quality - even a'phile stuff like soundstage width/depth , etc., is all there - on the same level as a good analog or digital set-up. providing ya have a station that broadcasts a quality signal, and a good antenna to catch it, that is!

and, ya can see my system in audiocircle's gallery, if ya tink it must not be hi-rez enuff for me to be making this kinda statement...
re: quality radio, i tink it's difficult, if not impossible, to find a decent broadcast of current pop/rock music. all the stuff i listen to is non-commercial radio. mostly latin/jazz/world, (89.3, wpfw - howard u) w/a touch of classical & npr (90.9, weta), a touch of bluegrass & npr, (88.5, wamu - american u), & one sometimes-good alternative/indie rock station from a li'l tiny wva radio station at shepard college (wshc - 98.7).
if/when ya can find out which philips model the ava is based on, (larry, any info here?), i am sure the folks at the yahoo tuna forum will be able to help ya...
doug s.