What’s the most underrated used Audio Research gear?

Sure, everyone loves the SP-8, SP-10, etc., but what about the sleeper ARC gear that’s still a good deal used? Recently got a used SP-17 and love everything about it for the price, but it got no love from either the press or the boards. 

Ag insider logo xs@2xideal8592

ARC D-79B and D79 were quite good.  ARC made a lot of underachiever tube amps.

@bpoletti - you hit the nail on the head.  PLUS once you upgrade them, they improve tremendously!  

The SP9 II & III ARE very good preamps.

I never understood the the criticism that they were or are lean. If they are then a warmer tube and or warmer cables will help if not cure. I have no problem the lowest of lows to come out of it let alone the mid bass.The soundstage to me is expansive and deep with well placed imaging, Especially with small room or close recorded material.Clarity, Dynamics are both exceptional IMHO. Nothing exaggerated even with the levels are turned up, no hardness or glare. i can only imagine the sound of the sp-11 ,sp-10. And for the price.