Just finished my 2 x 813 amp. Works great 80-10, but boy is this Amp Supply ATI-6 tuned input board driving me nuts. Finally got 10, 15 and 20 sections giving good swr to xceiver but 40 and 80 got me pulling my hair out. (I can't afford to loose much). Help! Anyone out there fought this before........................ Thanks, K6ZL