Although best known for its predominantly high-end, high-power amplifiers, Krell is a full-range manufacturer whose remit extends to AV equipment, loudspeakers and disc players of various types and levels of sophistication. In fact, the company produced what to many was the finest CD player of its day – the extraordinary but frighteningly expensive KPS25. Sadly, this player was discontinued when the supply of transport mechanisms dried up.
It was followed by the SACD Standard from the entry-level KAV range, which included multi-channel SACD replay in a unit costing about half that of the Evolution 505, the subject of this test. That model was introduced in 2003 and subsequently revised when the original mechanism became unavailable. The 505, Krell's third SACD player, is from the company's no hold's barred Evolution series, and adds more sophistication in design and construction as befits the higher price.
The 505 inside story starts with the use of separate discrete power supplies, built around a 65VA linear transformer for the drive mechanism and a 45VA transformer for the audio circuits, the latter optimised for Class A operation. Both work through with several stages of regulation to give a stiff, rock solid foundation, which has always been Krell's way.
Internal signal transmission is entirely balanced and in Class A throughout, free of feedback and the internal architecture operates in current mode, with a whopping great 500 kHz bandwidth.
Inter-component connections optionally use the proprietary CAST (Current Audio Signal Transmission) interface as an alternative to single-ended (for stereo or multi-channel) or balanced (two channels only) modes. In CAST mode, according to Krell, all linked components in a system operate effectively as a single component. There is only a single current-to-voltage converter stage in the whole system when used with a Krell CAST-equipped amp, minimising (Krell says eliminating) signal transmission aberrations, and effects due to cable impedance when transmitting signals in the voltage domain.
This is the first Krell SACD player with CAST, though the interface was part of the late-spec KPS25 CD player. Current mirrors operate using LED voltage references, said to result in a two-thirds reduction in harmonic distortion. The player is equipped with PCM1738 differential DACs on each channel, and in-house designed DAC reconstruction filters. Four SACD and two CD anti-aliasing filters are available to ‘fine tune' the sound.
