Well, that is a hard one. I am a long time Audio Research fan. My first was the SP-5… so solid state. I have had a ARC Phonostage since back then as well. Now all of my equipment is contemporary ARC Reference.
While there has been a little divergence from driving straight down the line towards the perfect natural / musical sonic reproduction. In general each step has been towards more detailed and dynamic reproduction without loosing the midrange bloom and rhythm and pace. So each five to ten years represents significant advances in the overall presentation. These steps each towards better reproducing the real thing.
I would find it hard to believe you would feel like you lost something by the move, but gained a huge jump towards bringing the real thing into your listening room. I am currently listening to Oregon… each instrument is suspended in space with perfect tone… fully fleshed out…
Anyway, given the probable value of your SP6… I would get the SP20 with the expectation that you will either get rid of it later, or not.
