Along with their flagship mono-blocs, Kora’s supplied their PR-140 line-stage. This one-box unit is also based on the Square Tube topology and is actually pretty impressive – especially at its sub-€6K starting price – but there’s no avoiding the fact that the CSA-1200s really deserve something an awful lot better. I used them with both the CH Precision L10 and L1/X1 as well as the Thales Magnifier pre-amp. All matched perfectly, especially given the Kora’s adjustable gain – reduced slightly for the CH units.
Although the CSA-1200 offers no chassis grounding post, the fact that it has both single-ended RCA and balanced XLR inputs invites the use of Chord’s GroundARAY devices. These worked beautifully, dropping the noise-floor, sharpening the focus, quickening the arrival of leading edges and bringing clarity and purpose to the dynamics. Play one piano track and you’ll be convinced. In the case of Claire Huangci Made in USA (Alpha 1071) the GroundARAYs brought clarity to and revealed the rhythmic precision of her playing, as well as a greater sense of note weight and attack, richer harmonics, longer tails and a far more complex ‘body’ to her instrument. The image gained presence, dimensionality and definition. These were not small differences and, once heard are hard to ignore. All the comments here regarding the Koras musical performance reflect their use with the GroundARAYs in place.
The other really worthwhile tweak was standing each amp on a trio of HRS Vortex footers, flat side up/points down. Despite Kora’s protestations (“They only need half an hour to warm up: it doesn’t matter what they are sitting on” – neither statement is true) the Vortex built on the improvements delivered by the GroundARAYs, with gains in dynamic range, clarity and a further drop in the noise-floor. Bass definition, the space around notes and their solidity increased, adding a more positive sense of pace and impetus where appropriate, a more anchored stability to large-scale acoustics. Icing on the cake? A pair of Acouplex Refracts placed across each top-plate and in direct contact with the heat-sinks, increasing the expressive nuance to voices and phrasing, revealing rhythmic subtleties and note shape, bringing the human element in the playing to the fore. Competent if rather staid in stock form, the Koras certainly aren’t short of those typical tube/Class A characteristics. But paying attention to grounding (mechanical and electrical) as well as chassis damping really brings those sonic attributes together, binding them into an impressive musical whole, sparking the amps to life, delivering a performance that‘s quite capable of competing with well against established benchmarks.
