I have the Avalon Indras and use Rowland M312 Amp and the Synergy lli Pre Amp with very good results. Have heard the Avalon Indras and Eidelon Diamonds with Pass 100.5's, Chord SPM1200MKll, Hovland Radia and Accuphase A50 at Quintessence Audio in Chicago.
If I was going to try a new amp it would be the Pass Labs x series. Very different from Rowland. Rowland was a tad warmer in the mid range, both exhibited sparkling treble with excellent timbre, slightly less prominent bass then Pass 100.5's, but; still tight and accurate. I found the overall coherence and soundstaging crazy good with the Rowland Amp. Both are great compliments with the Avalons.
If I was going to try a new amp it would be the Pass Labs x series. Very different from Rowland. Rowland was a tad warmer in the mid range, both exhibited sparkling treble with excellent timbre, slightly less prominent bass then Pass 100.5's, but; still tight and accurate. I found the overall coherence and soundstaging crazy good with the Rowland Amp. Both are great compliments with the Avalons.