Krell KSA-50S power amplifier Follow-up from September 1995
In my review of the $3300 Krell KSA-50S stereo power amplifier last month (Vol.18 No.8, p.165), an obvious point of sonic comparison would have been the $3495 Conrad-Johnson Premier Eleven A that Wes Phillips wrote about in the same issue (p.195). Time constraints, however, prevented that from being possible, hence the appearance of this Follow-Up.
For details of the system used, see my review of the AR 303 loudspeaker. The main loudspeaker used in the comparison was the B&W Silver Signature, although I also used the AR 303. The single-ended C-J was 5.7dB less sensitive (at 1kHz) than the balanced Krell; during the listening sessions, I adjusted for this with the Mark Levinson No.38S's accurate 0.1dB-step volume control. Both amplifiers were driven all the time; whichever wasn't hooked up to the loudspeakers was loaded by 8 ohm power resistors.
My first impression was how similar these amplifiers sounded. High-performance amplifiers must perforce be examples of convergent evolution, different technologies leading to the same excellent sound. When it came to the details, however, the comparison of the two amplifiers typified the tube-vs-solid-state debate. Both amplifiers had grain-free trebles, though the tubed amplifier's sounded more shelved-down with the AR speaker. However, the Connie-J's soundstaging was more billowing; the Krell's bass was more authoritative.
In the second section of "Don't Give Up," from Peter Gabriel's 1994 Secret World Live album (Geffen GEFD2-24722), for example, bassist Tony Levin plays a powerful reggae riff on his custom three-string Music Man instrument, heavily damping the lower strings (he used a Pamper to do this on the original studio recording, footnote 1). While the Premier Eleven had very similar extension on this sound, the bass guitar had considerably more slam with the solid-state amp.
On the other hand, while Paula Cole's reassuring second vocal line on the same track sounded a little more sibilant with the tubed amp, it was simply more palpably real.
Ever since I saw them live in concert in the early '80s, I've loved the Manhattan Transfer. The sound of their eponymous first album (Atlantic 7567-81493-2), however, is definitely low-rent. That's what you hear over the Krell—a flat soundstage, with an upper-midrange-dominant vocal sound and a bass guitar that's missing its fundamentals. Yet via the C-J, the vocal scat lines and Zoot Sims's tenor sax on "You Can Depend on Me" were better fleshed out in the lower mids, with the result that I could more easily ignore the recording's technical deficiencies. In general, I'm not a big believer in audiophile recordings. A good system should make the music accessible on even mediocre recordings, and this is where the Premier Eleven edged ahead of the KSA-50S.
Neither of these amps will be all things for all listeners. If you just have to have the most forceful presentation of rock music's low-frequency foundation, then the Krell will be the better choice. The Conrad-Johnson, on the other hand, will be the better amplifier for soundstage freaks and those in love with the sound of the human voice. You pays your money, you makes your choice. Be sure to listen to both.—John Atkinson
Footnote 1: Bass Player, May/June 1995, pp.46-56.