Audio Research Preamp Experts?

I understand that the SP16 was based on the 6s with there use of 12ax7s, is the older version a better sounding linestage, or did the improvement in parts surpass the older model, even though the 16 was an entry-level model. I also understand the LS5s are outstanding. The marketing engine says things are getting better, but I really do wonder some times.

Sleepers in the ARC line include:
LS2B, LS12, SP8, SP6E

Ethaby, could you compare the SP8 and 6E a bit more? That is the range I was thinking of. Not sure what changed between the E and the 8.

If you don't care about phono performance, it makes no sense to chase something like the SP-6, 8 and 10. They were outstanding in their days with phono, but their line stages are dreadful compared to the clarity, lower noise and greater dynamics of today's line stages.

As for the LS2 being a sleeper, this was hands down ARC's most sterile product of all time. If you want some 3D in your music like those older SP series units, but want much in the way of refinements over those, the LS5 is the way to go. The LS22 and LS15 later were sounds that went back to the LS2 signature.

I have a SP16 and find in to be a great match with my speakers and other components. I think you need to define what it is that you are looking to combine with your system. What is your goal?