I have acquired a D&A PDX-400 10 tube amplifier using (9) 6lq6's ranging from 92%-100% and (1) 6jr6 tube @ 100%. I am hitting it with 1 watt swinging approx 20 watts. Using a bird watt meter I can only get a maximum wattage output of only 535 on SSB and 375 or so on AM. I have read that these boxes are capable of doing better than this. Is there something that I should be looking at. The 3 transformers check good as well as th 8 electrolytic caps with no hum whatsoever. Any help would be greatly appreciated. Thanks, "313"