Adam, the JSX is voiced more towards the classic hard rock tones than the XXX. The JSX's Ultra channel is somewhat similar to the XXX's crunch channel, and the JSX's crunch channel is much more of a "crunch" than the XXX's crunch channel. There is more of a difference between the Ultra and Crunch channels on the JSX than the XXX. I had a XXX (actually 2 of them) and you can make it's Crunch channel sound exactly like the Ultra channel, and vise versa. Also, I've never heard about the tube/ss circuitry switching in the JSX :confused: that's a new one on me.

Originally Posted by: From Peavey's website on the JSXThis amp delivers sounds ranging from the Classic 50 to vintage British to the modern Triple XXX and all tones inbetween.

Also, depending on what type of tone you're going after, don't forget about the 5150/6505. Don't let anybody fool you into thinking that it is a one trick pony. I've got a 5150 combo, and can create just about any tone I want with it.