I found that the bass notes were the easiest to notice a difference when I ran the A1400 against my 3808, even when level matched with my trusty RS SPL meter. The mids and highs did have a slightly different airy/expansive sound to them that the 3808 could not offer except when I ran with Audyssey.

Are all these minor differences worth the cost of a separate amp? I say everyone has their own cost of diminishing returns etc. to consider....I still do not own a separate amp.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70