I first became aware of the significance of a system's amplifier with one of the first reviews of mine ever published: of the Krell KSA-50 amplifier, in the August 1983 issue of British magazine Hi-Fi News & Record Review. By May 1988, when I reviewed the awesome Mark Levinson No.20 monoblocks for Stereophile, I had become convinced that while a great amplifier can wrest great sound from modest loudspeakers, a modest amplifier will not do the same for great speakers. For the past few years, therefore, I have had on long-term loan an arsenal of monoblock amplifiers to try with the speakers I review: Lamm M1.2 Reference, Classé CTM-600, MBL Reference 9007, and Pass Labs XA60.5 (footnote 1); and, every couple of years, I drag out that original KSA-50 that I purchased following my 1983 review.