Preamp

dskinner5

The Ref 5 se has a high output impedance as measured by Stereophile especially in the bass. Steer clear of this pre with the X350.5’s input impedance of just 20k.
" Stereophile: However, at 20Hz the impedance rose to 1447 ohms balanced and 637 ohms unbalanced"

Being transistor the GSPRE should be fine, and I can’t find anything on the Mac’s output impedance at 20hz so being tube it has a ? on it.

Cheers George

I have heard that these 2 are a great match?

Is the impedence a problem mating the REF 5SE with the Pass X350.5, I`m not understanding the whole thing? Can someone explain this to me? 

The 4 preamplifiers that you mention may well be satisfactory. I urge you to explore the Sutherland Engineering model N1 preamplifier. I have been living with mine since January. I wouldn't let it out of my system for anything. It simply gets out of the way. Spectacular!

Benchmark DAC3?