Superb little amp. Compare with Aleph 5 - the Clayton is more powerful and more neutral, the Aleph sweeter. You will hear more variation from one recording to the next, and better bass control, with the Clayton. I used to own Quad 63's and had a highly recommmended CJ tube amp driving them, with the S-40 driving my Gradient subs. One day for some crazy reason I tried the Clayton on the Quads. Wow! Sold my CJ. The Clayton is that good. The only reason you see used Claytons at $1300 is that the brand isn't well known. They are a steal at that price.