How's Krell KSA80B compare to the latest model?

There is not much information on this older Krell KSA80B online and as such I would really appreciate your inputs on the performance and any suggestion on what is the best matching pre amplifier with it. I know Krell owned pre amp are the natural choices but I am planning to buy Sonic Frontiers SF1 to go with it. Anybody try that combination before? Is it true that the latest Krell are not full class A compare to the older model like the KSA80B?
I have owned a lot of Krell gear (although not the 80B) and as I went from one level to a newer one, the sound always improved.

I just upgraded from a KSA-200s to FPB 300cx. The improvement in high frequencies, impact, and inter harmonic detail was amazing. I ran the 200s with a SF Line 3 which was a very good match. The 200s is a little bright so a tube pre amp is a good choice in general (dont get the ARC Ls2b. That combo will drill holes in your skull.

Just upgraded the preamp to a Ayre K1xe for another improvement.
I think the mono version (Krell KMA 160's) are one of the great amps of all time. I don't really recall the SF1, how ever I really, really liked the Sonic Fontiers Line series. Depending on your speakers, room, etc. I think your might be onto something realy good.

Thanks for the response. I have another offer also to buy KSA150 with not much different in price. So that's a dilemma ,which is better among the two. I heard the KSA 15o is not fully class A.