I can comment on the Pass X-1 to the Ayre K-5xemp. The K-5 was the last piece to give me a full Ayre rack, and I thought it a little better than the Pass X-1 at the time, but I was going to change anyway.So I put the Pass back in the system today to check. On the Chesky Schererazade, I found the upper register on the orchestra to be a little more vivid on the Pass, and the lower register to be a little more articulated on the Ayre. Again in my system, I slightly prefer the Ayre, as a matter of system synergy, but with a Pass amp you might find a similar system synergy with the Pass X-1. The Ayre K-1 should be a notch above the K-5, but is normally more expensive. You pay your money and make a choice. In this case, you can't go wrong by much.