Which amp is a better choice for B&W 805s

You will get better sound with the 252. I've had B&W N804's, 803's, 802's and Signature 805's. They sound BEST with Mark Levinson. But your Mac's will sound great. I have had at times in my system Mac 402's and 501's. At my dealer friends the 252's on the new 804S B&W's sounds awesome!! Just my 2 cents....

I choose Mcintosh for my speakers. what i want to know is between Ma6900 and Mc252.which one give better sound? sorry my english is bad.

Like Mlawitm, I think Classe and McIntosh are good choices with B&W. In my case, however, I chose the MC275 for my 804s. I thought tubes worked really nicely with the aluminum tweeter in the 804s (which is the same as in the 805s). With diamond tweeters I might prefer solid state.

If at all possible, try and listen to both.

I think Classe and Mac are good choices for 805's but I chose Pass.