Krell KSA-50S power amplifier System

Sidebar 2: System

My digital front-end consisted of a Mark Levinson No.31 CD transport and an Aiwa portable DAT recorder, both driving an HDCD-equipped Mark Levinson No.30.5 via either a Sonic Frontiers UltraJitterbug or an Audio Alchemy DTI•Pro (original Star DSP version with v2.7 software) (footnote 1). My real-world digital source was a Parts Connection Assemblage DAC-1 processor. Digital datalinks included Madrigal, AudioQuest, and Illuminati AES/EBU cables and ASM Labs Mamba ST optical fiber.

The phono front-end consisted of a Linn Lingo'd LP12 fitted with an Ekos arm and Arkiv cartridge amplified via a Mod Squad Phono Drive EPS. Preamplifier was the remote-controlled Mark Levinson No.38S; comparison power amplifiers included Mark Levinson No.20.6 monoblocks, the Krell KSA-100S, and an original Krell KSA-50 that I purchased in 1983 and had updated to Mk.II status in 1986.

Loudspeakers were primarily B&W Silver Signatures connected via their integral silver cables and weighed down by lead-shot-filled Audio Ballast bags. Interconnects were AudioQuest balanced AudioTruth Diamond from processor to preamp, and balanced AudioTruth Lapis from preamp to power amps. Other than the No.30.5, all the front-end components were plugged-in to an API Power Wedge 116 AC conditioner fitted with the Power Enhancer meter option, itself plugged-in to one of the two AC lines dedicated to audio that serve my listening room. All the power amplifiers were plugged-in to the other line and were well warmed-up before I did any serious listening comparisons.—John Atkinson

Footnote 1: The sonic difference between these two jitter attenuators is interesting. The Sonic Frontiers has a more forward presentation, taking the Levinson setup in the direction of the SFD-2 Mk.II, while the Audio Alchemy makes the sound more laid-back but with a larger soundstage. Which I prefer depends on the music playing, with a slight nod given to the DTI.—John Atkinson
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