New Flex 6300 owner, well versed in SDR and Flex since the purchase of a new 1000 many years ago, then upgrading to a 3000 in 2009, and now the 6300. The transmitted audio in AM mode is out of phase as viewed on my oscilloscope. The audio is being fed at line level at the 15 pin d-connector on the rear of the 6300...pin one mic hot and using pin 5 for ground (unbalanced). This is exactly how I fed the audio into the 3000 with no inverted phase problem. I confirmed the improper phase by defeating the outboard audio using the hand mic supplied with the 6300, directly in to the front 8 pin foster connector, and the audio is still out of phase in the AM mode.