iFi GO BAR KENSEI: The Foremost Portable Headphone DAC/Amplifier

Kensei (translated as Sword Saint in Japanese) is an honorific title to a warrior that is well-versed with swordsmanship that reaches them to legendary status. The most well-known historical personality that carried this title was Miyamoto Musashi with his exploits on his sword duel with some of the best swordsmen of his era and his authorship of The Book Of Five Rings.

Portable headphone amplifiers also known as DAC/Amp dongles are modern peripheral devices that are equipped with some of the recent breakthroughs in audio technology like better circuitry, system on chip that handles audio decoding/encoding process and other components to improve audio signal output to have a clean, clear and detailed sound quality for better high fidelity experience. It became a staple device for audio enthusiasts who still want a high quality sound even while on the move while having that mobility to be carried anywhere that will be used on their smartphones, laptops and tablets.

iFi is a UK-based audio company and it is a subsidiary of Abbingdon Music Research also known as AMR which has an extensive experience on releasing some of their audio product models in the high-end audio market from CD music players up to the loudspeakers. This audio company released tens of portable audio apparatus like USB filter devices, music streamers and headphone amplifiers since 2012 and most of them are priced from affordable entry-levels up to the midrange tier level. They also have some strong R&D department and also have their own factories across the globe that ensures technological audio innovation and the consistent quality of their products.

I did a previous review on their iFi Go Link Max and I find it excellent on how iFi is able to deliver a product at reasonable price, and now I have on my hand right now is their latest and probably one of the best portable headphone audio market, the iFi Go Bar Kensei. This model is actually a variant the previous model, the iFi Go Bar but it has some added new audio technology features and build material that distinct itself from its precursor.

The iFi Go Bar Kensei shares some design profile with other portable headphone amplifiers that are currently found in the audio market, an elongated rectangular shape slab with USB type-C port, dual headphone jack in different analogue output and some LED lights for status indicator. But this type of device is probably the hefty one that I ever held as it exhibits premium quality that ensures durability and finesse.

The overall body of this one is entirely made of high quality Japanese stainless steel (I wonder if this one is actually made of Tamahagane, a type of steel made from from an iron-sand which were used on making high quality katanas and other bladed weapons) which are known for its high carbon content for its malleability and toughness due to its low impurity content while achieving the hardness and wear resistance. All sides of the panels have a brushed surface as it has some metallic lustre and consistent fine grains for less fingerprint smudges and resistance from light scratches, scruffs and nicks as it also exhibits that elegance and sophistication of its overall aesthetics. Also, I was trained as a chef that I can impart some of my experience on having high quality kitchen knives that were made from Japanese stainless steel, it makes cutting and slicing some meat and vegetables easier and improves productivity in the kitchen. Although premium stainless Japanese  knives are pretty expensive, I have a Gyutou and Santoku ones that I bought for a second hand price but I digress.

The left side of the panel is where the button keys are located along with a toggle switch. The physical key section consists of three buttons, one for sound setting modes and two for volume control that feels tactile and snappy to press just to have that satisfying click to feel. The volume buttons have finer increments on adjusting volume level according to your preferred volume level. The toggle switch is use to activate iEMatch for 3.5mm and 4.4mm balanced output which is one of the core proprietary audio technology that iFi Audio developed as it works as an load impedance regulator to address the issues of some highly sensitive ear/headphones (ahem….CA Andromeda) that produces unwanted noise floors due to impedance mismatch by eliminating those audible background noise by means of complex circuitry for stable signal transmission while  delivering an appropriate impedance load to the ear/headphones. The right side panel doesn't have any buttons but it has a small sticker with QR code.

On the front panel, the surface has a laser-etched print of the iFi brand logo, the word “Kensei” in Kanji script and the model name along with hi-res audio certification sticker below. Meanwhile, at the back panel, there we can find a number of small LED lights that are used as an indicator for audio format, sample rates, sound profile modes and even volume level.

There are 9 LED lights that were arranged vertically along with some printed audio formats (PCM and DSD), sample rates (44kHz, 96kHz, 192kHz, 384kHz on PCM, 64(2.8 MHz), 128 (5.6 MHz), 256(11.2MHz) on DSD), MQA decoding, XSpace and Xbass mode.

The control of its digital sound filters has a cycle arrangement, it starts with Off mode and it ends with XSpace + XBass mode via short presses on every mode.

• Off mode
• XSpace mode
• XBass mode
• XSpace + XBass mode

To activate the K2HD mode, press the digital sound filter mode button for 3 seconds then press the increase volume button. It also applies to MQA mode on accessing its full decoding mode.

Another feature that this device has was its digital filter settings as it offers 4 types of custom digital filter modes.

DIGITAL FILTER MODE	COLOUR CODE	DESCRIPTION
Bit-Perfect Mode	Cyan	No digital filter, No pre/post ringing. For pure and natural tone.
Standard Mode	Red	Modest filtering, modest pre/post ringing. It delivers a tighter response on low frequency and a bit elevated but regulated high frequency.
Minimum Phase Mode	Yellow	Minimal pre/post ringing with slower roll-off. Produces a warm,  analogue-ish sound profile.
Gibbs Transient Optimisation Mode	White	Minimal filtering with no pre-ring and minimal post-ring. Delivers an elevated upper-mids and presence treble for better resolution and clearer details.

K2HD is algorithmic mastering process that was co-developed by JVC and Victor that  enhances the bandwidth of an audio spectrum  to sound more richer, more dynamic and more clarity and extension on nuances as it restores harmonics on high frequencies via advanced decoding for audio reproduction and also, it greatly reduces jittering while improving the processing performance on its time-domain signal.

MQA is a digital audio encoding technology that was developed by Meridian Audio and its audio process is through unfolding with software decoding and hardware decoding for better streaming and save up some memory storage although its compression method for a  “higher resolution” is still in a lossy format state as it somehow dispute with the moniker  “Master Quality” which should be equal to bit-perfect audio playback.

XSpace and XBass are proprietary sound enhancements produced by iFi as the former will improve the spaciousness of its sound field akin to listening to a well-placed speakers in a wide room while the latter mode will add more depth and impact on its overall bass reproduction.

At the bottom part, there we can find the audio output interface with two headphone jacks of different output, a standard 3.5mm and a 4.4mm balanced which are the current norm for the current audio enthusiasts. The internal 4.4mm port was gold-plated while the 3.5mm has a black-coloured rim on its opening port. Just like the Go Link Max which is its entry-level alternative, this one also has a proprietary S-Balanced technology on its 3.5mm port which greatly reduces noise and cross-talk up to 50% for fuller sound output on regular single-ended ear/headphones.

The upper width part panel is where the USB type-C port was situated that will be used for connectivity to a host device through sync for audio output decoding. The connection seems quite stable and firm as it provides a secured insertion.

It looks that upon viewing the device in this cross-section angle, it has an unusual hexagon-shaped reminds me of a silhouette of a large flat-roof house.

On its internals, Go Bar Kensei is equipped with the latest breakthrough in portable audio technology in the form of microchip and other components like capacitors and oscillators/ attenuators. It is known that most of the iFi products uses Burr-Brown DACs but this time, it uses a custom-made Cirrus Logic one which is known for its reliability and consistent audio quality to sound clear and detailed, excellent audio signal processing performance while maintaining a low power consumption.This audio IC is a 32-bit two-channel stereo DAC that can deliver a power output level up to 2 VRMS, and also, its supports sampling rate processes up to 384khz and a DSD playback support up to DSD256 with advanced components that reduces distortion and less jittery.

Another important component that this device has was its built-in XMOS iC microcontroller which has a 16-core configuration with a low latency that also greatly improves processing power due to increased clock speed and increased memory along with a faster USB speed delivery. This iC microcontroller also works in tandem with its fully-customised femto-precision clock oscillator, GMT (Global MasterTiming) to eliminate jittering issues for pure audio reproduction.

As for power output level, both audio jacks deliver a powerful output that is capable of driving some of the power-hungry, high-impedance headphones in the market.

HEADPHONE JACK OUTPUT	POWER OUTPUT LEVEL (Normal Gain;High Gain)
3.5mm S-balanced	300mW @ 32𝛀, 3.8VRMs @ 600𝛀
4.4mm balanced	475mW @ 32𝛀, 7.2VRMs @ 600𝛀

Note: To activate Turbo mode or high gain mode, press both the volume level buttons for a few seconds after pressing the sound filter mode button.

When it comes to  product packaging, this is probably the fanciest unboxing that I've ever experienced on a portable USB headphone DAC/Amplifier on how its contents are presented in an organised manner. It has a wooden box where the contents are stored with a Japanese-inspired pattern on its sliding top, which makes its overall presentation more elegant with its wood craftsmanship to admire.

Here are the following contents we can find inside of its well-crafted wooden box storage:

• iFi Go Bar Kensei  Portable USB DAC Headphone Amplifier
• Leather Case
• USB Type-C to USB Type-C OTG cable
• USB Type-C to Lightning cable
• USB Type-C to USB Type-A Adapter
• Paperwork like quick guide and user’s manual card.

This device itself is universally compatible to all known operating systems on the software side and it's also sync to other modern devices that support USB audio support like smartphones, tablets, laptops and PCs. I’m testing this one on my smartphones, laptop and tablets, and all of these devices connect well without any issues at all.

Gadgets that were tested for this product assessment:

• LG G7 (Android 9)
• LG V40 (Android 10)
• LG V50 (Android 12)
• LG V60 (Android 13)
• HiBy R6 PRO II
• HiBy R8 II
• Lenovo laptop (Linux Mint OS)
• Apple iPad 6th Gen

List of headphones and IEMs that will be used for this testing:

• LETSHUOER EJ07
• LETSHUOER EJ07M
• LETSHUOER EJ09
• LETSHUOER CADENZA 12
• LETSHUOER DX1
• DITA AUDIO Project M
• BQEYZ Winter Ultra
• SIVGA Que
• SIVGA ANSER
• SENDY AUDIO AIVA II
• HiBY ZETA
• 7TH ACOUSTIC SUPERNOVA

Note: Hearing a sword swishing sound effect signifies a stable sync connectivity between this peripheral device and its host device.

As for its tonal performance, the overall evaluation will be based on its stock digital filter tuning which uses the bit-perfect mode and it has this their interpretation of balanced-neutral type of sound profile with sufficient warmth which retains that iFi’s in-house flavour tuning.

LOWS/BASS:

This device produces a rather correct and accurate bass response as it presents a more balanced bass presentation. It has a clear sub bass presence and an adequate mid bass texture to deliver that snappy, precise and tactual sound to neutral-sounding sets with a rumbling end of its overall sound.

It is capable to present a clear and reverberating sub bass that were generated from electronic, strings and percussion instruments, while its mid bass texture is pretty sufficient to give a proper note density on some bass-clef instruments and deep male vocals with low octave as they sound more resonant, rasping and sustaining.

Activating the XBass will enhanced its low frequency as it adds more depth and vivacity on its bass quality without too much colouration but if you paired it with bassy sounding set, it will further augmented its bass response to sound more dynamic and impactful that bassheads will enjoy its more authoritative sound.

MIDRANGE:

Neutral, pristine and quite transparent with a well-balanced texture on it. It has a tad of warmth presence that somehow adds a bit depth and volume thats will make the vocals and instruments sound more life-like and organic as it has that musicality factor rather than too sterile and dry sounding that were usually tonal profile of an extremely detailed “audiophile” high fidelity tuning. It delivers a more natural sound on male vocals as the baritones have a smoother and plushness sound while tenors have a brassy and juiciness sound from their vocals, and then, a more tender and emotive sound on countertenors from their falsettos. On female vocals, it produces a powerful, smokey and strong chesty voice from contraltos, a golden and velvety sound on mezzo-sopranos, then a creamy and satiny sound from sopranos.

As for instruments, as I mentioned a while ago that they all sound quite natural and accurate  with a minimal to none of embellishment on their respective tonal colour. On string instruments, guitars have balanced to a midrange sound, violins have full, sensuous and clear sound, and double basses sound mellow, lustrous and lyrical. The brass instruments with the likes trumpets, trombones and horns, trumpets sound full and brilliant, while trombones have a solid and rounded sound, and horns have full and glossy sound. About woodwinds, concert flutes have light and ethereal sounds, piccolos with their graceful and brilliant sound, clarinets have their lustrous and rich sound and saxophones sound reedy and mild. In regards to percussive, snare drums have those hard and penetrating sound on every stroke, and same with tom-toms with its warm and resonant sound, field drums have their majestic and full sound, and last but not the least, kettledrums sound deep and substantial. The pianos seem to have a balanced tone as it has clear, sweet and rich sound on them.

HIGHS/TREBLE:

This device delivers a relatively neutral presentation in this part of frequency as it presents a more balanced sound with enough gleam and smoothness with sufficient amount of air. It renders well the clarity and definition for more articulate vocals and an intensity of attack on instruments that it doesn't need to emphasise some part of its treble section.

This device is able to present a good sparkle and it depicts the timbre of some selected treble-clef instruments like cymbals, glockenspiels and celestas with their respective sound characteristics; brilliance, silvery and shimmering.

OVERALL TECHNICAL PERFORMANCE:

Expected for high calibre portable USB headphone amp, it offers an excellent technical performance as it can project a fairly spacious sound field in a clean sonic background with remarkable layering and separation that is almost on par or even equal with some of the best desktop-grade headphone amps that I’ve tested so far.

Another qualities that this device has was its resolution capability as it has very firm macro-dynamics that it was able to highlight the varying degree of loudness level from quite to loud that even on the strong amplitude level, I didn't encounter any clippings or distortion at all, while its micro-dynamics is very competent on extracting a good amount of transients, note textures, notational attacks and reverb tails. In general, this device retains a semblance of musicality with that depth, rich and life-like quality that iFi in-house sound are known for while reconciling with superb technicalities that are usually a typical characteristic of analytical headphone amplifiers either in a portable form or a desktop one.

PEER COMPARISONS:

QUESTYLE M18i

• Questyle’s latest portable headphone DAC/Amplifier that shares similar audio interface output configuration with the Go Bar Kensei but has some new features that the latter device doesn't have.
• This one has a larger size as it accommodates some components and it has an OLED screen to display the status of its digital audio format mode, sample and bit rate and  active device mode.
• It uses a ESS DAC, ES9219Q which is also known for its superb audio processing and also a low-powered one too.
• While it has proprietary CMA module technology, it doesn't have any sound enhancement, digital sound filters or any advanced audio processing that Go Bar Kensei have like XBass, XSpace and K2H2.
• This one has a small built-in battery for wireless bluetooth capabilities that also supports advanced bluetooth codec and also has a HD microphone that is capable of receiving calls.
• It has a warm-ish neutral sound profile as it has some slight warmth on its overall sound profile.
• It can deliver a good powerful output that is also capable of driving some power-hungry headphones, and also has excellent technical performance.

QUESTYLE M15i

• One of the premiere portable headphone amplifiers that Questyle has to offer as it has a similar profile with Go Bar Kensei.
• It has similar size with the Go bar Kensei but it has a tempered glass window where we peek upon its internal parts like CMA tech, DAC chip, headphone amplifiers and other components that were embedded in a circuit board wafer.
• It uses a flagship ESS USB DAC, ES9281AC which is an even more powerful audio processor that on paper it can decode up to 768Khz on PCM and DSD512 on DSD format.
• It has a proprietary CMA module technology, but it doesn't have any features that Go Bar Kensei has like digital sound filters and advanced sound enhancements like XBass, XSpace and K2H2.
• It doesn't have any button for volume adjustment but Its toggle switch to change gain output mode is much more convenient to operate than the two button mode that Go Bar Kensei has.
• This one has a balanced-neutral sound that is quite similar with the Go Bar Kensei’s tonal profile.
• It delivers a powerful output that is able to drive some high impedance headphones and also has a competent technical performance like good resolution capabilities from its clean pitch-black sonic background.

AUDIOQUEST DRAGONFLY COBALT

• An old flagship USB Headphone Amplifier from Audioquest and their third model from its Dragonfly series.
• It has a lighter,slimmer and compact size compared to the Go Bar Kensei.
• This one is equipped with ESS DAC, the ES9038Q2M which is also flagship with good audio processing performance albeit an older generation one and doesn't have a native DSD support.
• This one has an unusual configuration as it has a single-ended output and USB Type-A connector that will most likely be used on PCs and laptops.
• It doesn't have any sound enhancements or digital filters that Go Bar Kensei have.
• This one has a balanced-warmish tonal profile that makes it more coloured and analogue-ish sounding.
• It has a sufficient power output enough to drive some power-hunger headphones and earphones but it wont simply match the power output of the Go Bar Kensei even on its normal gain mode and its technical performance seems competent enough to present a clean sonic presentation.

As I conclude this product review, this device is certainly one of the best of its class right now as it truly that tonal and technical prowess that can be only rivaled by desktop-grade headphone amplifier and what makes it more astonishing was its incorporates some of its proprietary audio technologies than can only be found on their desktop models like the Xbass, XSpace and K2HD that makes it more compelling and formidable. Its overall build quality also speaks for itself as its premium material also fits well with its product’s theme.

The overall performance of Go Bar Kensei is seemingly striking a balance for both technical excellence and a neutral tuning that preserves the musicality bearing that iFi is known for with  its depth, detailed and organic sound without any compromises. The iFi Go Bar Kensei is currently available on iFi Audio’s official site. If you are interested in purchasing this device, I just provided a non-affiliated link below.

LINK:

https://ifi-audio.com/products/go-bar-kensei/

More iFi product review?

■ iFi GO LINK MAX

SPECIFICATION:

MODEL: IFI GO BAR KENSEI

OUTPUT POWER: 300mW (SE); 477mW (BAL)

INPUT MODE: USB TYPE-C

OUTPUT MODE: 3.5mm + 4.4mm

DNR: 109dBA

THD: ≤0.002% (6.5mW/2.0V @ 600 ohms

SNR: 132dBA

SAMPLING RATE: 32bit/384kHz

DSD: DSD64/128/256

DAC CHIP: CUSTOM CIRRUS LOGIC

MATERIAL: JAPANESE STAINLESS STEEL

DIMENSIONS: 65 x 22 x13.2mm

NET WEIGHT: 65.5g

PROS:

● The overall structure is pretty solid  as it is made of a block of high quality Japanese stainless steel.

● Incorporates some of iFi’s proprietary audio technologies; XSpace, XBass and S-Balanced.

● That IEMatch toggle switch will definitely solve the unwanted noise floor issues from overly sensitive IEMs   

● It has a custom Cirrus Logic DAC and other components that will work with it. 

● Can decode up to 32-bit/384kHz on PCM and DSD256 on DSD format.

● It has 4 digital tuning filters to choose from.

● Delivers a powerful output on both 3.5mm and 4.4mm balanced for  power-demanding ear/headphones.

● Physical button keys on volume control and sound filter mode, and they are quite snappy and responsive.

● Definitely one of the well-presented product packaging that I have encountered for a portable headphone Amp/DAC.

● Inclusions of USB type-C to lightning cable and USB type-A adapter for other device compatibility.  

● It has a Turbo Mode/High gain mode to drive some of the high impedance headphones.

● It has a balanced-neutral type of sound profile

● Produces a clean, clear and detailed organic sound.

● Excellent on its general technical performance.

CONS:

● A bit hefty for a dongle use.

● Doesn’t have an advanced built-in EQ. 

● Lack of bluetooth connectivity for wireless transmission.

● Need some muscle memory on operational familiarity to access other features. 

● Since there is no built-in battery, it will drag some power from its device host.

TESTING TRACKS: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)

Alison Krauss -When You Say Nothing At All *

Jade Wiedlin - Blue Kiss**

Led Zeppelin - When The Levee Breaks **

Mountain - Mississippi Queen *

Queen - Killer Queen **

Guns N' Roses - Patience *'*

Eric Clapton - Tears in Heaven '*'

Sergio Mendes- Never Gonna Let You Go '*'

Pearl Jam - Daughter **

Roselia - Hidamari Rhodonite *

Assassin - Fight (To Stop The Tyranny)*

Celtic Frost- Visual Aggression *

New Order - Blue Monday *

The Corrs- What Can I do (unplugged version) *

Jimi Hendrix Experience - Voodoo Child *

The Madness- Buggy Trousers *

Metallica - Motorbreath **

Mariah Carey- Always Be My Baby *

Destiny's Child - Say My Name *

Malice Mizer- Au Revoir *

Mozart - Lacrimosa *

New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *

Eva Cassidy - Fields of Gold (Sting cover)*

Michael Jackson - Give In To Me *

Exciter - Violence and Force *

Diana Krall - Stop This World **

Debbie Gibson - Foolish Beat *'*

The Sisters of Mercy – Lucretia My Reflection**

Suzanne Vega – Luka **

Lauren Christy – Steep *

Ottoman Mehter - Hucum Marsi *

Diana Damrau - Mozart: Die Zauberflöte*

P.S.

I am not affiliated to IFI AUDIO nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.

Once again, I would like to send my gratitude to the iFi Audio Rep for providing this review unit. I truly appreciate his generosity and trust towards me and other reviewers.