upgrade from Audio Research SP6C

Hi, I have a SP6C with VT100. I like the 3D sound of SP6C. I compared it side by side with CAT SL1, Krell KRC-HR, SP9, LS7 and SP16. The CAT is very neutral. KRC-HR is more focused and has better image. LS7 is so sweet in mid but lack of bass. SP9 and SP16 are also on neutral side. None of them has lush 3D sound as SP6. My favorite media is female vocal. I also have 30% rock and classic music in my library.I heard a lot of positive for Conrad Johnson. That brings me a question: should I try CJ preamp? Which CJ model should be a upgrade from SP6? Or should I go up with SP8 or SP10? I don't know if there is a big difference between SP6 and SP8/SP10?
Cygnus_859, Check out the Exemplar XP-2 preamp. I have never owned a preamp that even comes close to this unit.
Cyngus 859, IF you heard a correctly set up CAT SL1 you should have heard a MAJOR MAJOR jump in SQ over your SP6C. I had an SP8 in my system and I can tell you the CAT is in a whole different league. To really hear what the CAT can do, you have to have upstream gear that can let the CAT shine. I also believe to get the last few ounces out of the CAT, tube rolling is recommended.
The SP10 Mk2 is also a very good preamp, BUT still not quite up to a CAT, IMHO.
The SP-6C is good, the SP-3C is better if you like a warm tube sound. The 3C has a recently updated FET regulated power supply. The SP-8 is a better sounding preamp than the SP-6C.and sounded a lot like the SP-6E as they both had tube regulators. I owned an SP-6B for many years and found it to be a bit lumpy in the bass.
I may have missed the good side of CAT SL1. I use a Classe CAV150 when I demo it, which it not good enough for the preamp. It didn't give me a vow at that time.