ARC recommended the same 20k for my old ARC pre-amp which had a 600 ohm output (I assume the same output as the Ref 3). Ran it with an old Threshold with a high input impedence and another anp with a 10k input impedence. The mismatch (I'm told - I've never actually heard the result of a mis-match) causes a rolloff in the highs which will be precieved as such and a consequential softening of the bass (FWIW the sound of 'tight bass' is IMHO more of a result of
the correct presence of the high frequencies in a drum when struck or a bass when plucked).
For myself, I wouldn't be concerned with an impedence mis-match on you present system. Too bad you can't try that system with tubes - then you will have something to really be concerned with that you will actually hear and not just fret about! :-)
the correct presence of the high frequencies in a drum when struck or a bass when plucked).
For myself, I wouldn't be concerned with an impedence mis-match on you present system. Too bad you can't try that system with tubes - then you will have something to really be concerned with that you will actually hear and not just fret about! :-)