As a matter of fact, you should not hear a difference between Class A and Class AB if both amplifiers operate within their rated output limits. Only people who claim to hear a difference might have "golden ears" and are unable to prove it with double blind tests.\n\n\nIt would be interesting to do a DBT study on golden ears ability to score consistently higher than 50\/50 using DUTs make up of say 3 class AB amps, 2 upper mid range AVRs and 1 XPA-1 (X2) based on 0.5W average output level and 64W peak and then find out if they can rank, say 10 DUT roughly in the same order.:D\n\nMy speakers of choice for such test would be a pair Revel, or KEF Reference series speakers with sensitivity about 88 dB @2.83V\/1M and the participants will sit 10-13 ft from the speakers in quiet acoustically treated room. For preamp, I would use one of the well measured (by ASR) desktop DAC that has good volume control. \n\nI don't think it is hard to do such a study if a few AH members (such as RichB and Boomzilla) would volunteer to organize one. I would volunteer HD and you to be the observers during the DBT sessions and ADTG to contribute the amps and AVRs (since he's a dealer).