If you listen in a small room and at low levels you should be able to get by with a 300b amp (8 to 10 watts/channel). Antique sound labs has a number of SET's at reasonable priced that are triode based or pentode based in the 8 to 10 watts/channel range. My preference for SET's runs towards higher power. An 845 based amp will deliver about 20 watts/channel and should light up your Coincident speakers. You will have to find a used 845 based amp to be in your price range. If you decide to go higher power, let me know, I have an Antique Sound Labs 845 based amp that I am willing to part with for a little more than you target price. By the way, EL34's can be run in single ended configuration.
How to pick your first SET tube amp?
I am curious about hearing one of these little amps on some new monitors I got, the Coincident Triumph Signatures. Coincident makes a beautiful pair of SET mono's, but at $3500 they're a little steep for experimenting with. Any recommendations for a good, entry-level pair of SET monos that would give me a taste of what all the fuss is about? I would like to stay at or preferably under $1500. What is the difference between the sound of the EL-34 based SET's and the 300B and other types?