Best Integrated Amp for PSB Image T6 Speakers

I currently have an NAD C356BEE driving my PSB Image T6 speakers and am not too happy with the sound. Despite "tuning" the placement of the speakers numerous times, the music still sounds flat. The room is large (18'x26') and my listening position is about 12' from the speakers. I hooked up a friends old NAD receiver (C740, 35 WPC) and the system sounded better. Any suggestions on a different int amp? Thanks.
For $1299, you really should audition the Rogue Audio Sphinx.
It's a Class D/tube hybrid that will give your system dynamics in spades.

To fit your budget, there's also the Marantz PM8005 for $1200 USD. 70 wpc/8 ohms, 100w/4 ohms with tone control bypass.

or look for a used Ayre AX-7, may be hard to find.
Another vote for Rogue Audio Sphinx at that price point. Stereophile's latest issue said it kicked the crap out of hard to drive Magnepan .7s.
If you're ok with a used integrated amp, the Primare I-30 would be a good choice. There are lots of good reviews on this integrated amp out there.