Preamp

dskinner5 OP
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?

Manufacturing a product that is dependant on being a good impedance match and having much experience in it now, you should strive for a  output impedance to input impedance ratio of 1 to 20 or higher There is no "written in stone" set ratio, this is just my own observations, some say 1 to 10 is fine, but I think that's cutting it too close. 

The Ref 5se has an output impedance in the bass of 1.447kohm, this multiplied by 20 equals 30kohm the Pass is only 20kohms as advertised.

This is why I said "being transistor the GSPRE should be fine" as it should be far lower that the 5se's 1.447kohm and a better low to high ratio match with the Pass.  

Cheers George 

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