I remember Nelson Pass commenting on HK amplifiers. In fact, the Citation 12 was one of his first 'MOD' jobs. He spoke very highly of their design and sound. I have an audio buddy who uses a Citation 12, with the DQ 10's. Very nice system. His preamp is a Citation 1 tube unit. I wish I had that preamp, the sound is incredibly warm, smooth and sweet. Makes you want to pour a good Brady or Scotch and listen for hours. I wasn't aware of the Fulton connection, but that really does make sense. The amps surely do have a unique sonic signature that keeps you coming back for more.
Have you ever opened up a Citation 11 preamp or one of their amps? The Build quality is outstanding. At least on the order of McIntosh. I don't understand why HK and Citation don't get more 'respect' in the audio community. Their product are all very robust and have excellent sound.