Sonus Faber Stradivari amp: X600.5 or X1000.5 ?

Extreme levels! That's not safe.

If you listen at a lower level, your ears will open after a few minutes. You will actually hear more of the music and deeper into the recording.

The X.5 series is a relatively good value, and can provide brute force. But as Onemug said, you are paying for quantity rather than quality. The XA.5 does the power thing quite well, while also providing finesse and beauty. It comes down to priorities.

Rtn1:

A few days ago i listened on my system the X350.5 and pushed the ARC REF3 to 60-65 and it was very loud. The amp was in perfect control of the speakers without any distortion or compression. The metter of X350.5 was over the half.

Johnb30,
I asked Kent at Pass about the XA100.5 versus the X350.5 driving a difficult load. He told me that in listening tests, the panel preferred the XA.5 and mentioned sonics but also its ability to control low frequencies and low impedances speakers. My speakers are a 4 ohm load and only 86dB efficient, so I switched from the XA100.5 to the XA160.5. With your speakers, you should have no trouble with either, IMO. I suggest you talk to Pass Labs and then demo a pair from RENO HIFI or a local dealer to be sure before you buy.

Ive just ordered a pair of XA160.5. In max one month it should be here. Thanks for all advices and i hope i will be very happy with my new pair of amps.
Thanks.

Ive just received the pair of XA160.5 yesterday. The sound is very good but it still needs some break in time. Does anyone knows how long it takes for XA160.5 for full break in ?