03-23-11: Sm2727I just replaced a SS phono stage with a tubed (Jolida) one in my otherwise SS signal chain and the difference was immediately noticeable. How noticeable such a change would be would also depend on the low level resolution of the downstream components. A mid-'80s Adcom is going to obscure more of the tubes' traits than a Class A Nelson Pass, Krell, or Classe', or even an A/B amp heavily biased into class A.
Thank-you all for your responses. I just didn't want to pay for tubes in the front end only to find that those tube qualities I am after don't survive the the solid state translation.
I may replace my SS line stage with a tubed one but I'll probably keep my SS amp for the control and stability it exerts over my speakers.