New PrimaLuna versus used Audio Research preamp?

I own a REF75SE  which I love so far but my gut feeling is everyone here is recommending ARC preamps is because of the name and reputation which I get however, have the same guys recommending ARC owned or had the EVO series preamp in their system? 

You might want to consider an SP-10MKII. Or a Ref 2. Ref2 had tube regulation as well as a 5AR4 for rectification. And 6922, which had the magic missing from 6H30 preamps. IMHO. SP-10MKII is amazing. SP-11MKII is also great,but a hybrid and has a different presentation that is an acquired taste.

Nobody I know can answer how any of these compare to a PrimaLuna without listening in an instantaneous A/B comparison that is level-matched to within .5dB, and double-blind. It’s not possible. If anyone is in L.A. and has a REF 6 or similar they want to bring out, we can host. And who knows. I might be wrong. We did this for some Agon guys years ago with some LAOAC members, and the VSI75. What was shocking was how close good gear is to each other.

If you strip away the obvious prejudice of getting a massive discount from a high, retail price and look at circuit design, quality of parts, and sound I think you would be rather shocked.

only ARC preamp I like is the Ref 10. the LS series is sterile and SS-like. 

I'd try a Primaluna first and roll the tubes. or an LTA MicroZOTL.

“the LS series is sterile and SS-like.”

This is why many make the distinction between the LS and Reference series of ARC line stages. They aren’t one and the same.