In many ways, rather than the previously defined continuum between tube and (push-pull) solid-state amplification, the performance characteristics of these Kora amps sits somewhere at right angles, on the left turn towards direct heated triodes. It’s a realisation that helps explain Bruno Vander Elst’s suggestion that these should really be considered tube amps: as he points out, the amplification is all triode. It’s implementation and the implementation of the output stage means that that quality (or character) survives through to the speakers. I’ve listened to a lot of hybrid amps over the years, including the extremely impressive (and “impressive” is the word) Aesthetix Atlas Eclipse and Trilogy 995R, but of them all, only the TEAD Linear B – an amp that plays its own ‘triode output’ card – comes anywhere close to the sound of the Koras. The Evans amp is of course, an ‘inverted hybrid’ in the sense that it uses solid-state input circuitry coupled to a composite-triode output stage and output transformer. By placing its tubes right at the input and eliminating the output transformer altogether, it’s not hard to see how the Kora amps might preserve more of the input/driver stage’s linearity and phase coherence. Achieving that goal in practice is a lot more difficult, yet it’s a goal that Kora has demonstrably achieved, while adding bandwidth, serious power and load tolerance to the mix. Try as I might (and I really did try) I could hear no difference between the CSA-1200s’ high current and auto switched settings – suggesting that this is one sort of ‘clever’ that actually works. The result is an amplifier that can appeal to those who love the naturalistic presentation and tonal qualities of triode amplification, the fluidity and rhythmic articulation of well-executed Class A designs, but value the scale and bandwidth of larger speakers. It’s a potent combination, especially when it comes to musical expression.
No, the Kora CSA-1200s can’t match the dimensionality, scale and sheer power delivered by the big VTL amp(s). They can’t match the musical and structural clarity, immediacy, transparency and sheer information of the CH amps. But they offer their own, compelling musical benefits. It’s a more specific and compelling blend that “the best of tube and solid-state”. What the Koras offer is a unique mix, at least as far as I’m aware – triode sound with genuine power, harmonious harmonics with the responsive dynamics that come with proper load tolerance. Yes, you can buy big, single-ended triode amps, with huge output tubes, but they lack the rhythmic, textural and dynamic subtlety that make the Koras not only so intimate and enjoyable to listen to, but intimate and enjoyable with a whole range of speakers. In keeping with their retro styling, I revisited the age-old hobby of little speaker/huge amp combinations, hooking up the Neodio Lillis to the CSA-1200s. It’s not a combination I’d recommend, but I’d be lying if I didn’t admit to the silly grin it evinced. All about subtlety and musical integrity, the little Lillis just loved the sheer colour and density delivered by the Koras, the amps putting flesh on the bones of the speakers’ astonishing musical articulation.
