What class is my el34 amplifier

I recently became the owner of a pair of tube monoblock integrated amplifiers that were custom designed and built for a local discriminating audio enthusiast. I don't know why but he never used them and has moved from the area so I'm unable to contact him for more info or to find the builder. These amps have 4 EL34 pentodes each with a switch of unknown function. I have owned two Cary amps both of which had similar switches allowing a choice of running the amp in ultra linear or triode mode. It makes sense that is the same. The other option could be to accommodate a different tube, I suppose. Even though these are integrated I'm using them as power amps powering Martin Logan Ethos speakers. They sound wonderful especially in the upper mid frequencies. 
Anyway, I'm using them and they're beautiful and sound great but I would really like to know more about them. I don't have schematics so I'm just looking for suggestions re what these switches might do.