So, what we can assume here is that the Kensei is mechanically better than the original. And – as mentioned – has also better isolation from the harmful outside interference. And since we have the enclosure covered, let’s focus on the inside workings. When you compare the detailed description of the Kensei to two other Bars (original one and the Gold version) – you’ll notice some variations. First one that is unique to the Kensei, will be the “Ultra Low Jitter” clock circuitry in the Japanese-inspired edition (vs. the “Standard Low Jitter” in two older models). This is how iFi Audio explains this:
“As a part of our continuing efforts to improve the performance of our products, we have made improvements to the oscillator in the clock circuitry, which has resulted in lower overall jitter. This is reflected in our decision to refer to 'ultra-low jitter’ in relation to the performance of the GO bar Kensei.”
Fair enough, better clock is always a welcome improvement especially since everyone nowadays understands that this directly leads to the better sound. The other difference, this time shared with the Gold model would be the “Enhanced Power Supply”. The explanation here is also simple and straightforward:
“The GO bar Kensei is fitted with improved capacitors in comparison to the standard GO bar. This results in better filtering of noise from the power supply section of the circuitry, reducing the noise floor and improving the overall listening experience.”
So, summing up all of the above – better enclosure, better clock and improved power supply. Until now everything should be perfectly clear. So, to make things more complicated and more interesting at the same time – here comes the K2HD technology. You may obviously ask what it is, and good people from iFi Audio come with an explanation:
“It optionally upsamples depending on programme material’s sample rate. K2HD isn’t only upsampling though; it’s processing waveforms via the time domain through DSP to effectively interpolate missing frequency content and bit information with lower resolution material, to match the tonal characteristics of the original master. The reason why K2HD is so revered compared to other „digital filtering” is because it is inherently very musical sounding, as JVC engineers at Victor Studios Japan spent 18 months refining the K2 parameters against original masters (of which they have 1000+) to close the difference in sound quality.”
Let me give just a bit of a historical context here. K2 technology was initially developed by JVC in 1987 together with Victor Studios and – looking from more audiophile standpoint – found its way into much revered CD Players like the JVC XL-Z1050 and the JVC XL-Z999. Those players did indeed sound very good and many well-informed enthusiasts knew that there was that “K2 Interface” chip JCE4300 involved. It was also dubbed “the mystery chip” and was placed after the CD servo and before the digital filter silicon in the whole circuit. In that case – the K2 Technology can be seen as one of the first successful attempts to fight jitter long before that word even became as known and as well-worn as it is today. What is also important here is that the K2 technology evolved over the years and now is actually a set of technologies that focus on preserving the original sound quality while working in the digital domain.
We also need to realize here that the K2HD technology is not a digital filter per se, it doesn’t act as one, neither is a substitute for one. Because – on the contrary to how the original K2 Interface chip worked back in the day (of CD players) – the nowadays version with the “HD” in the name works actually after the digital filter stage (if there’s any present). It’s especially important to notice this in the light of the fact that we have a GTO (Gibbs Transient Optimized) filter that normally would up-sample everything to 352.8 or 384 kHz, but with the GTO setting and the K2HD technology enabled – the up-sampling frequency of the latter will be 192kHz instead of the 384kHz just mentioned. iFi Audio explained the actual difference between the GTO filter and the K2HD technology as well:
“The GTO filter upsamples 2-8x to 352.8/384kHz and has a slightly different impulse response characteristic – it has no pre-ringing and minimal post ringing. This gives the impression of enhancing details and density within a track. K2HD optionally upsamples (i.e, if a track is 192kHz, it does not upsample), and then does its proprietary waveform processing. In fact, in our recent interview (I will provide a link below), Hideyuki Akimoto, the sound quality master from the technology research group for the future creation research laboratory of JVC Kenwood, noted that the K2HD technology and GTO filter complement each other particularly well, with the GTO filter helping to showcase the detail and nuance that the K2HD technology offers.”