I'll add to what Charles1dad said regarding the Cary's: Don't judge a 300b by it. I love/have their 845/211 based 805 AE's but their 300b SE monos just weren't for me (had them/sold them). I don't know if it's because they run it so near the max's but I did not hear the sweetness I hear from my Art Audio Symphony II or my very favorite custom 300b amp.
FWIW, the "right" 300b amp is at the top of my favorites list, mated to the right speakers of course. I have Maggie 3.6's in another system and bought the Cary 805 AE's to see if I could get away with using a single ended amp on them and it's working for me. This amp uses a 300b to drive the 845 or 211 choice of output tube. Even though it's an 845/211 amp, rolling different 300b's in them gives me some different flavors I enjoy. If you find you need a more powerful amp, these might do it for you. Older ones might be in your price range. Try and go for one with a 300b driver if you can.
FWIW, the "right" 300b amp is at the top of my favorites list, mated to the right speakers of course. I have Maggie 3.6's in another system and bought the Cary 805 AE's to see if I could get away with using a single ended amp on them and it's working for me. This amp uses a 300b to drive the 845 or 211 choice of output tube. Even though it's an 845/211 amp, rolling different 300b's in them gives me some different flavors I enjoy. If you find you need a more powerful amp, these might do it for you. Older ones might be in your price range. Try and go for one with a 300b driver if you can.