When I went all balanced it was a nice improvement in control and dynamics. I know they say there's a conversion to balanced when using single ended but when I put the last step, going balanced from CDP to preamp things really improved. Read the Pass manual about the patented balanced circuit, it seems to make sense to take advantage of it for optimum performance.

I personally would think the X1 would provide as much improvement as the X250 over an AVA amp. The X1 is older but it's a two chassis quality piece. .