Here is my design which is built and in the testing phase. The only change anticipated at this time is a better coupling cap between tubes. I am looking into Mundorf MCap Supreme SILVER/OIL caps to replace the Wima caps. My plan is to use a Beta 12LTA. The enclosure is a 2.5 cu ft. PiAlign by Wayne at PiSpeakers. The tweeter is a Fostex FT17H. Tweeter and crossover parts are on order. I have attached a link to my site which has schematics of the amplifier.