Pass Labs XA-160 vs Levinson 33H

At least we have a level-headed comment here from Output555.

Why not go for a Tenor amp? At least you will have some nice wood to look at while going crazy over its sound.

I don't want to be categorical, but I think the amp/speaker interface is far more important than the preamp, not that preamps are not important - they are, but the power/current/and ability to drive a speakers impedance is critical, most noticeably in the ability to produce deep bass where impedance dips in some speakers will make some amps compeltely incapable of producing satisfyin bass. I would think that the amps mentioned could drive most any speaker - so not a problem. But driving a 10Kohm amp input impedance is a problem with most (not all) tube preamps. It would not suprise me if the ARC is not getting the best from your Pass, but I'm not sure what the ARC's output impedance is. WHat does ARC say about driving the Pass?

ARC recommends 20Kohm input impedance at least. My Pass is 22Kohms input impedance. Am I too close to the lower limit??? Would getting something with higher input impedance help? If so, in what ways can I expect a high input impedance to improve the sound?

Pbb,
I guess brains was a poor choice. I was quoting someone else. I suppose a better choice of words for the amp would be the muscles and nerve center. Bottom line is correct matching of amp and speakers taking into consideration room size and choice of music and headroom needed.

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! :-)