I am using the Purifi Eval 1 for my Kef LS 50 Metas and the Aiyima A07 for my Kef CTC 3005 SE Center channel, and I don't notice any difference in tonality, nor do I play things loud enough to clip anything. So, as far as I'm concerned, as long as it's not pushed the $80 Aiyima should be transparent. You can also beef up the power supply and get it to deliver over 100 WPC for not much more than $50. It's in one of the Aiyima threads somewhere.
The step up amp would be the 252, and the state of the art would be the Eval 1.
The step up amp would be the 252, and the state of the art would be the Eval 1.