Ifi says its latest portable DAC restores the missing quality in digital audio

Ifi Go Bar Kensei.
Ifi Audio

Wired headphone and in-ear monitor (IEM) fans now have a new option when it comes to hearing bit-perfect digital audio on the go: Ifi’s new $449 Go Bar Kensei takes one of the best portable headphone DAC/amps and adds two made-in-Japan technologies.

On the outside, the Go Bar Kensei’s chassis is made from Japanese stainless steel — an homage to the blades wielded by legendary Japanese swordsmen that also lends the DAC better structural integrity.

Ifi Go Bar Kensei.
Ifi Audio

On the inside, however, is arguably the more important Japanese contribution — JVCKenwood’s K2HD Technology — which Ifi says “works to restore music to the same quality as the original master, reviving it with the rich, natural harmonics” that are apparently lost during digitization.

A diagram showing how JVCKenwood's K2 technology restores CD audio quality.The claim is that, since CD-quality audio (which uses a sampling frequency of 44.1 kilohertz) only preserves audible frequencies of up to 22kHz, these digital recordings fail to capture the extended high frequencies (and their accompanying harmonics and overtones) that exist in natural audio.

K2HD attempts to restore these higher frequencies by upscaling audio files to a sampling frequency of 192kHz and applying K2 parameters for waveform shaping, which processes the time domain, not the frequency domain. In theory, these upscaled hi-res audio signals should offer the equivalent of audible frequency extension of up to 96kHz.

K2HD isn’t the only technology that attempts to improve CD audio by making adjustments to the time domain. MQA, a digital audio format supported by the Go Bar Kensei, claims similar improvements.

Whether K2HD makes an appreciable difference to your music or not, it’s one of several selectable digital filters on the Go Bar Kensei, including Ifi’s own bit-perfect, standard minimum phase, called Gibbs transient-optimized (GTO), plus two analog filters, XSpace and XBass+.

Interestingly, Ifi says the Kensei outperforms its other Go Bar models when it comes to audio quality thanks to its enhanced power and clock circuitry, which provides a wider soundstage, resolution of “every musical nuance” and deeper, cleaner bass.

Ifi Go Bar Kensei.
Ifi Audio

As with Ifi’s other Go Bar models, the Go Bar Kensei has both a balanced 4.4mm output and an unbalanced 3.5mm output, along with a selector switch that can can engage Ifi’s IEMatch technology for either port. This attempts to reduce noise when using highly sensitive IEMs.

Each port should be able to drive even the most demanding headphones and IEMs, with the balanced jack offering a claimed 477 milliwatts at 32 ohms and 7.2V at 600 ohms, and the unbalanced jack offering 300mW at 32 ohms and 3.8V at 600 ohms.

In addition to being a full MQA decoder, the Go Bar Kensei can handle PCM audio up to 384kHz, and up to DSD256 audio.

The Kensei comes in an engraved wooden box, along with USB-C and Lightning-compatible cables, a USB-C to USB-A adapter, and a carrying case.

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