The output tubes are 41's in PP, but the OPT is center tapped 'off' center. There is no phase splitter. The bottom tube's grid is feed off a screen of the top tube. They only use 175v on the plates. Strange, but it sounds good. I had no idea there might be good used field-coil speakers. I think I'll try to find a permanent magnet one though. I'm not really trying to keep it too original. I do love the looks of it and the vintage sound.Thanks for the speaker specs.
Tom