Lafayette KT-600 Stewart Hegman Design

Well, I have debated about telling my Audio Friends about this.  Years ago in one of The Absolute Sound Issues, HP raved about a refurbished Stewart Hegman designed preamp...Lafayette KT-600.  So I finagled by hook or crook to get one..and a factory wired one.  Chrome faceplate etc.  It came with Sylvania grey plat 7025s and the midrange and top end were as HP described.  The bass sounded like an old Dynaco Pas 3???  So after 10 years of listening and having the power supply rebuilt and "beefed" up by two different highly regarded technicians....$$$$$......it still sounded very similar.  Improved a little, but no bass.  After much disappointment, I put it on the shelf for several years.  Then finally I had to try it out again after finding a Mark Levinson No. 23.  I am not a transistor guy at all, but I thought the Levinson would help the bass. Still no bass.....and then while listening to Dire Straits... I switched the little brown knob on the lower left....rumble filter.  It was wired backwards or put in upside down ;(.  I thought it was only for the phono......wrong......Holy Cow....The Infinity Watkins  and other speaker's woofers...came to life. I feel like an idiot.  FYI for you Audiophiles...the lower midrange and up to the top end,  the Lafayette KT600 sounds like the old Quicksilver 8417 monos or even the Citation II.