I've owned the X600.5 and now have the XA200.5.
As good as the X.5 series is, it sounds hard and 2D compared to the XA.5 series. For large orchestral pieces, the suitably powered XA.5 series wins easily because the climaxes remain sweet and undistorted. The X.5 gets harsh and glassy at peaks.
There were some changes from the XA to the XA.5, which I wonder may have resolved some of the issues with peak distortion and the sense of unlimited power reserve.
I've posted my thoughts and descriptors of the XA200.5 on the forum if you do a search. The descriptors remain true even today. In my view, the XA200.5 is a masterpiece, with the only downside of heat. My amps are the muscles in a synergistic combination with key components of preamp and cabling. As good as the amps are in isolation, the BAT, Jade, Tripoint, NVS Sound combination has taken things to another level.
As good as the X.5 series is, it sounds hard and 2D compared to the XA.5 series. For large orchestral pieces, the suitably powered XA.5 series wins easily because the climaxes remain sweet and undistorted. The X.5 gets harsh and glassy at peaks.
There were some changes from the XA to the XA.5, which I wonder may have resolved some of the issues with peak distortion and the sense of unlimited power reserve.
I've posted my thoughts and descriptors of the XA200.5 on the forum if you do a search. The descriptors remain true even today. In my view, the XA200.5 is a masterpiece, with the only downside of heat. My amps are the muscles in a synergistic combination with key components of preamp and cabling. As good as the amps are in isolation, the BAT, Jade, Tripoint, NVS Sound combination has taken things to another level.