Best Integrated amp for under 4k

I had the yba integre dt which was very nice, the audio refinement complete an astounding value, the McIntosh MA6450 a superb unit, and now the McIntosh MA-6500.

The McIntosh MA-6500 has incrdible sound, looks and features. Although expensive, worth every penny!

How about the older Krell models 300/400 series?

I'm currently using a Krell S-550i Integrated Amp. to power a pair of Wilson Audio Sasha 2 Spkrs. in a large room and it sounds very good, with excellent dynamics, micro-detail, imaging, and deep bass, plus plenty of good clean power.

I recently ran a $7,500- Pass Labs INT-150 against it and the Krell performed far better across-the-board, with what seemed like twice the power - it was no contest.

The Krell S-550i reminds me more of my previous Pass Labs X1 and X250.5 combo. than the INT-150 did, it's that good and could be had for well-under your budget.

Given that this thread has been resurrected, I'll offer my two cents. 

Musical Fidelity M6si