Buying a used amp for $2500 with out auditioning

First of all, the cj and the bryston 4B-ST will not cost anywhere near $2500 used. A 4B-SST might cost closer to that amount. You'd also do well to get two used 7B-ST monos for that price, but it might happen. I'm not familiar with the Canton speaker, but I suspect you are worried about how the tweeter will perform with these unauditioned amps. Well...you probably need to mention what preamp you use and maybe what type of music you like. Without knowing, I would suggest the brystons as not being too harsh. I own bryston and cj stuff (tube and ss).

The Bryston 4B-ST and 4B-SST are excellent amplifiers, but may not be the best "fit" with your Cantons, which can be rather hard and bright with the wrong amp, so I am reluctant to endorse your plan to buy an amp without auditions. Of course, if you get get a prospective seller to allow you a few days to audition the amp, with the right to return it, you could solve that problem.

As the previous post noted, the Bryston 4B-SST can be purchased used for around $1800-2000 (it's still a very new model), while there is a 4B-ST with 17" faceplate currently listed for sale here on A-gon for $1200.

Go for it. Read as much as you can about each candidate, narrow your choice to one and find a good deal. The worst that can happen is you won't like it, so put it back for sale, maybe you will lose a few hundred bucks but you gain a home audition and a wealth of knowedge. I purchased one amp brand new for 2400.00 without ever hearing it and it is my favorite, a keeper for the rest of my life. I purchased another one used here on Agon which I'd never heard before and am happy with it although it's probably not a keeper for life.