I have had the opportunity to own the FPB 200, 300 & 600 Krell amps. The "C" series amps work best with their front end source "Cast" equipment, basically if you are not using the "Cast" technology in source equipment the early FPB series will suffice. I do think that cosmetically the newer faceplates on the "Cast" units look better. So if you're in to looks. Each unit is underated as for as "WPC" are concern as Krell has been known to be real conservative in rating their amps in "WPC". A past stereophile review on the FPB 600 confirmed tests of over 900 WPC with test on the FPB 300 exceeding 400 WPC. Have not seen a written article on testing of the FPB 200, would think it is rated above the 200 WPC. Used the 200 & 300 model on some VR 4's with the 300 producing wider soundstage and tighter mid bass. The 200 is by no means that far behind, the 300 just broadens the presence a little better. The FPB 600, well it's in a class of it's own and was used on some real ineffecient speakers that brought them to life, they basically danced around each night. They will run hot which is nice in the winter, in the summer I just turned up the "AC" and enjoyed the music with a higher electric bill at the end of the month. The hotter they get, they better they sound! I still find that they run cooler than the earlier "S" series amps. The top end is by no means harsh to me ears, in fact from a solid state unit I found it very pleasing and non-fatiqing. The mid-bass is the best I have heard from any amp and which I find to be the hardest to reproduce by many amps. The bass, well, nothing like it, tight, fast and presise! Slap in "Edwin McCain's" "Honor Among Thieves" and enjoy!! I have since changed speakers which incorporate servo control on the bottom end and currently run tubes on the top end. How I do miss those amps. As mentioned earlier the FPB 300, to my ears, produced a wider soundstage and tighter mid-bass. Good luck in your decision.
