Cayin Audio were R2R pioneers in a smart music player, but the advent of the R2R RU6 USB-C DAC/amp dongle establishes them as masters of the fully-discrete resistor DAC topology in portable audio. Entering 2022, this is all it takes to achieve the buttery, natural and resolving sound, plus imaging depth, R2R is known for. Building a discrete R2R DAC in N6II/R01 had already been no mean feat. Yet to have gone one further, and implemented a 4.4mm DAC dongle for Android, iPads and laptops is a most ambitious step for R2R. It's worth it to Headfonics who cite RU6's "analog" approach, and the innovation extending to its volume control is lauded by Headfonia. [See Product Desc. For More] It gets harder every time it gets smaller, so RU6 marks Cayin as masters showcasing how they can make it work. Descended from R01, RU6's boasts a chain of 96 0.1% precision, temperature stable, resistors. That imparts a fidelity to mobile audio not yet experienced. Over 200 mW of balanced power gets most earphones and headphones loud, on the move. ecoustics say RU6 "is not only very unique but also one of the best of its kind". Everyday Listening rates "RU6’s wide stage and analogue-like note presentation granting it one of the sweetest and most euphonic sounds I’ve encountered". After thorough comparisons with other options, Twister6 qualifies RU6 as capable of replacing entry-level music players. Prime Audio Reviews confirms it differentiates itself from other DAC/amps, and it's Ear Fidelity's Best Portable DAC of 2021. Your music will be decoded up and down RU6's 24-bit ladder of individual resistors, crammed into its thumb-sized chassis over two separate six-layer PCBs. The actual R2R ladder DAC is kept apart from signal processing to lower noise. We pay attention when Cayin implement RU6 ala typical R2R – with a NOS (non-oversampling) mode. That's double the feat because the precision demanded goes up. Amidst minimal digital filtering, R2R's analog-like goodness gets delivered unmolested to your ears. Lovers of reference sound need not fret, however, with RU6's ability to switch from NOS to oversampling mode for the cleanest possible result. That scrubs any last distortion and artifacts beyond the audible human hearing range, leaving you to just enjoy your music, naturally, via one more Cayin innovation yet. That precision is backed up by a low-power, fully analog, volume control solution. A series resistor operates with shunts as voltage dividers in tandem with relays, to maintain near-perfect resolution of your music and a signal-to-noise ratio of over 110 dB. A totally novel volume solution has made this a feat for a USB-powered dongle DAC; let alone a R2R one.  Take all 30g of the RU6 built from CNC aluminium with you in your pocket, bundled with a USB-C cable as stock for all your mobile devices, with additional leather cases and Lightning-to-USB-C cable (not MFI-certified) sold separately.  Also check out the rest of Cayin's releases here, or view our other DAC/amps here.

An utterly modern device, GO blu reflects iFi Audio's understanding of new-age listeners. This Bluetooth 5.1, LDAC and aptX HD receiver is also a balanced 4.4mm amplifier, giving you all the power you need with a battery life of up to 10 hours. And, it's as small as your AirTag. How iFi stuffed in its balanced circuit, Qualcomm QCC 5100 Bluetooth receiver and outboard Cirrus Logic CS43131 DAC chip is a closely guarded secret they won't be telling anyone in a hurry. [See Product Desc. For More] Convenience aside, GO blu is a genuinely audiophile design with boutique parts and an attention to circuit detail – including direct coupling – that belies its use cases and form factor. Headfonia puts this iFi through its paces, and it won this race. Just like What Hi-Fi? awarded GO blu 5 ⭐ and an Applause Award followed from StereoNET. Headfonics love "it's appropriately named a pocket rocket because that’s what it is". MOONSTAR Reviews echoes that praise. That's proven in iFi's USB-C socket that doubles as charging input and wired DAC input, if you'd like the ultimate in pocket fidelity. Enjoy it to its maximum via the 4.4mm cable supplied with Audio-Technica's MSR7b – or at home with any one of iBasso Audio's SR2 or Focals via a CB17 cord. See what more iFi can do in larger form factors here, or view our other portable DAC/amps here.

1-bit, multiple possibilities. After the debut of Head-Fi's first discrete 1-bit, all-to-DSD, music player in N7, Cayin Audio have miniaturised the technology further in RU7. This latest novel 4.4mm USB DAC/amp from innovators Cayin therefore promises to upsize your enjoyment of music with the same decoding topology that saw N7 greeted with aplomb. Built of 128 individual resistors, RU7 converts all your normal PCM playback – via CD rips, Hi-Res downloads and Spotify, Tidal or Apple Music streaming – into DSD before decoding to analog. Its size is proof that no task is too big for Cayin. Outputting in 4.4mm, RU7 is Cayin's perfect complement to the PCM, R2R, RU6. Headfonics says RU7 is "the best of the lot". Headfonia elected this mini DSD masterpiece to its Recommended Buys list. eCoustics add "it's the best dongle DAC we’ve tried yet". "RU7 continues the company’s hot streak of breaking new ground in DAC design ... 1-bit DAC in the RU7 is even more impressive than the R2R DAC [in RU6]" says The Headphone List. To Twister6 and ichos-reviews, RU7 even challenges DAPs. Bringing up to 400 milliwatts power to bear, the goodness of an all-to-DSD approach to decoding can be heard with all manner of portable Head-Fi. [See Product Desc. For More] All audio formats are passed as DSD through RU7's precise 1-bit decode. Cayin returns to Sony's Scarlet Book SACD revolution of the 1990s and elevates that conversion philosophy with modern mobile dongle hardware. RU7's highlight is its 1-bit decoder, converting all PCM files to quad-rate DSD first via DSP logic, while letting native DSD material flow on to the 128 discrete resistors in its DAC – in actuality a simple analog low-pass filter. There's zero error at the point of conversion in a 1-bit DAC. There, Cayin relies on Pulse-Density Modulation (PDM)'s total accuracy, and sheer ease of decoding. The pitch for DSD's 1-bit conversion is digital at its simplest and closest point to analog – level represented only either as a 1 or a 0, switching on or off. To achieve analog, the bitstream is simply low-pass filtered. Cayin's all-to-DSD discrete DAC is accurate ... and also elegant, breakthrough and historic in personal audio. It draws inspiration from the illustrious halls of Hi-Fi, where each EMM Labs, Nagra Audio, Playback Designs, PS Audio and of course, N7's, 1-bit DAC release has been greeted with accolades and fanfare. RU7's discrete proprietary tech immediately differentiates itself from commercial DAC chips, where IC packages are often too small to perform an ideal 1-bit conversion. RU7 also avoids the errors of dynamic element matching inherent to 2-7 bit delta-sigma decoders. The decoded analog goes through Cayin's specially designed resistor-based analog volume control for perfect channel matching at any level – facilitating that very special 1-bit discrete DSD decode and importantly preserving your music's true dynamic range resolution. A series resistor operates with shunts as voltage dividers in tandem with relays, to maintain near-perfect resolution of your music and a signal-to-noise ratio of over 110 dB. A totally novel volume solution has made this feat possible on a USB-powered dongle DAC. Cayin differentiates RU7 from RU6 in offering the former a line-out option whereby the volume control is bypassed for a fixed voltage out, perfect for listening into motor stereo systems as well as handy and portable personal speakers.  Meanwhile, RU7's 400mW output power is doubled compared to RU6's, such that this DSD DAC is capable of transferring all its forward-thinking fidelity into your prized transducers. Never fear for leaving your reference gear behind for Cayin's latest and greatest every-day carry.  There ends the list of exploits worthy of celebrating Cayin's 30th anniversary in arguably more ambitious a way than even N7 offered. Check out the rest of Cayin's gear here, or view our other USB dongle DACs here.

xDSD Gryphon is the host with the most, but in reality it's possibly the most focused recent offering of technology from iFi Audio. Most, if not all, of iFi's latest innovations in the arena appear in xDSD Gryphon – for the single-minded enjoyment of portable and desktop listeners alike. It goes straight onto Headfonia's Recommended Buys list, and sounded excellent at all times on Headfonics. [See Product Desc. For More] xDSD Gryphon is transparent while not being afraid to have fun doing so. Playing in stock configuration, it keeps the beat going and your listening always engaging and apace with the track. Audio-PH say it's a "complete device in all respects, harmonious and balanced in everything". Gryphon takes 5 ⭐ from T3. Gryphon is perfect to help your spacious, reference, gear like Audio-Technica's AWAS, Empire Ears ESR II, Oriolus Traillii, Rosson Audio Designs and Sennheiser's HD800S live a little. A true balanced, differential PureWave circuit co-designed by Hi-Fi legend John Curl makes its smallest, most portable appearance yet to add correct colour to life on the move. Size is no excuse for compromise and xDSD's power stage is direct-coupled for extended bandwidth into the lowest frequencies for excellent phase reproduction and fast-sounding bass. Gryphon may be tiny but is mighty, putting out up to 1,000mW of power in balanced 4.4mm. Eschewing global negative feedback in favour of local feedback for a more natural sound, PureWave is a true high-performance circuit befitting of your flagship earphones and headphones. A digitally-controlled analog volume control preserves resolution and the low noise of xDSD Gryphon, while maintaining perfect channel balance and tracking even at minute volume. This control christened CyberSync overrides all other controls from your sources, leaving you no doubt that your xDSD is operating at maximum dynamic range with no unsuspecting digital attenuation going on where it shouldn't happen. Never worry about missing bits again. All this technology befits a wired connection via included iOS Lightning, USB-C and USB-A OTG cables. But in a pinch xDSD Gryphon transforms into an aptX Adaptive, aptX HD and LDAC Bluetooth receiver with Qualcomm’s new QCC5100 Bluetooth chip feeding the master Burr-Brown DAC. XSpace, XBass II and a Presence control round off a list of features, none of them redundant and all fully focused on pure musical pleasure from xDSD Gryphon. View its bigger iDSD Signature brother here, all iFi's other hits here, or our other portable DAC/amps here.

New and improved USB-C to 4.4mm second-generation audio amplifier by Ibasso.  2 x CS43131 DAC Chips Up to 32bit/384kHz PCM Decoding  Up to 256x Native DSD Decoding with a THD+N below 0.00032%  High Power Output of up to 195mW@32Ohm, 4Vrms@300Ohm

From the original creators of the portable DAC/Amp as we know it today: Audioquest follow up with the Dragonfly Cobalt, on the back of the rave Dragonfly Black and Dragonfly Red. [See Product Desc. For More] Digital audio has moved on from the very earliest days. Cobalt comes brought up to speed with ESS Sabre's latest ES9038Q2M, MQA decoding and an adherence to minimum-phase reconstruction for the smoothest yet most detailed sound yet. Coming with its own USB-C adapter for smartphone, tablet and Apple iPad use, Audioquest have thought of everything in their most mature product yet. Please view their options here or our other DAC/Amp ones here.

Your iPhone doesn't have a headphone jack? Here's how you keep wired, and get everything to sound better. The detail put into the design of this MFI-certified iOS DAC and amp lies not just in its great sound, but also in the user's ability to charge and listen to music at the same time. AAW's Accessport empowers listeners with great sound, and the battery to keep the tunes flowing.

Questyle Audio adhere faithfully to current-mode amplification at all form factors, and building a 4.4mm balanced output into the M15i just extended the capabilities of their flagship dongle, which now comes with MFi certification for guaranteed usability with Apple products. Headfonia says "M15i offers one of the most sophisticated designs in the industry". ecoustics rate it on par with legacy music players and "would suggest trying it before you pay for anything else". MOONSTAR Reviews echo M15i competes on equal terms as music players. Headphonesty hail it as liquid gold. M15i "managed to wring musicality out of the ESS DAC chip that I frankly did not think possible" praised Headphone Guru. It's Highly Recommended on Ear Fidelity. It's easy to hear why, if audible results count to you. Operating in current-mode, audio signal gets passed in current instead of the more standard voltage. The Raven, Odin & Legend Evo from Empire Ears provides instant synergy, given their 3ohm load. Current-mode amplification eliminates the lag time of the signal that might otherwise occur, as it builds up at the capacitances in the circuit – current signal passes through unhindered as compared to voltage, with speed and ease. [See Product Desc. For More] By doing away with the issue of transmission delay in M15i, Questyle virtually eliminates any of the harshness caused by the intermodulation distortion associated with high capacitance, solid-state circuits. Typical of their high-end offerings, M15i decodes digital via its ESS Technology ES9281AC DAC smoothly and organically, without exaggerated warmth or bloat.  That small signal then takes advantage of being unhindered by capacitance in the signal path. An added benefit from current-mode amplification is that huge signal bandwidth is possible, leading to phase response being accurately preserved in the human hearing range. Indeed, to hear current-mode is to hear a naturalness to music not encountered before in a conventional circuit, and Questyle build M15i as an affordable entry to such a topology. Happily use with any low-impedance device (current signals excel the closer a load is to ground) such as Rosson Audio Designs, the Vision Ears Elysium EXT, plus CIEM heavyweights Craft Ears and Empire Ears – particularly the latter's Odin and Legend Evo. Driving low impedances is M15i's forte. But bridge-tied load balanced operation now means this dongle also doubles voltage swing compared to single-ended operation, to drive higher impedances credibly too. Explore how Questyle's current-mode scheme in can further benefit your planar-magnetic headphones in CMA18P, or browse our other mobile DAC/amps here.

In response to the newest generation of challenging flagship earphones comes the Questyle Audio CMA18P 4.4mm DAC/amp to rule them all. Battery-powered, this AKM AK4493SEQ current-mode monster runs the Empire Ears Raven and Subtonic Audio Storm with ruthless, total capability.  Questyle adhere faithfully to current-mode amplification at all form factors, and build the ultimate version of M15i. And – with four desktop-class current-mode amplifiers, and a built-in battery power supply to free CMA18P from the handicap of USB's 5-volt source – the capabilities of their now-flagship portable just got extended. It's easy to hear. Operating in current-mode, audio signal gets passed in current instead of the more standard voltage. Certainly, headphones from Focal, Fostex plus HIFIMAN, Rosson Audio Design and ZMF Headphones could not ask for a better 4.4mm portable source. And Raven, Storm, and Symphonium Audio's Crimson all provide instant synergy, given their low impedances – and current signals excel the closer a load is to ground, mimicking a dead short. [See Product Desc. For More] Even before CMA18P's power and signal arrive at the final destination – your flagship earphones and headphones – current-mode amplification is already working its magic. It eliminates the lag time of the signal that might otherwise occur, as it builds up at the capacitances in the circuit – current signal passes through unhindered as compared to voltage, with speed and ease. By doing away with the issue of transmission delay in CMA18P, Questyle virtually eliminates any of the harshness caused by the intermodulation distortion associated with high capacitance, solid-state circuits. That small signal then takes advantage of being unhindered by capacitance in the signal path. An added benefit from current-mode amplification is that huge signal bandwidth is possible, leading to phase response being accurately preserved in the human hearing range. Indeed, to hear current-mode is to hear a naturalness to music not encountered before in a conventional circuit, and Questyle build CMA18P as a portable TOTL expression of such a topology.  Now working with Asahi Kasei Microdevices (AKM)’s resurgent AK4493SEQ and a XMOS XU316 USB receiver for a pristine digital decode, the analog section of CMA18P preserves the converted audio to present it smoothly and organically, without exaggerated warmth or bloat. For those who wish to experiment with other sources, a pair of line-ins are also included. Happily use CMA18P with any low-impedance device bolstered by four desktop-level current-mode amplifiers as Questyle's purest portable voltage source yet.  CMA18P pushes gear such as Focals, Fostexs, HIFIMANs, Rosson Audio Designs, and CIEM heavyweights Craft Ears, Empire Ears – particularly the Raven, Odin and Legend Evo – and Vision Ears effortlessly. Driving low impedances is CMA18P's forte. Still, the bridge-tied load balanced operation with four amplifiers outputting means this Questyle also doubles voltage swing compared to single-ended operation, to drive higher impedances like HEDD Audio's HEDDPhone 2 and ZMF Headphones' Caldera credibly too. CMA18P is all you'll need with the low-impedance gear you'll commonly carry outdoors or at work. Otherwise, explore how Questyle's current-mode scheme in CMA15 can further benefit your planar-magnetic headphones at the desk, or browse our other mobile DAC/amps here.

The smaller iBasso Audio's engineering gets, the more ridiculous their feats get. So it is with DC Elite – virtually a miniature DX320 Max TI. It goes right onto Headfonia's Recommended Buys list. Headfonics adds "it's a monster of a dongle DAC" and Twister6 adds iBasso stepped it up with DC Elite. "iBasso's DC Elite redefines what’s possible from a portable DAC/Amp dongle" says MOONSTAR Reviews. DX320 Max TI was groundbreaking because it brought a discrete stepped resistor analog volume control to the fold. So how then should Head-Fi react to DC Elite packing exactly the same ridiculous marvel of engineering, in dongle DAC/amp size? DC Elite's stepped volume attenuator, developed in-house from individual resistors by iBasso, is where the money is at. It's that that enables it to play it delicately into your flagship earphones for enjoyment at realistically lower volume levels. Together with the resolution of ROHM's BD34301EKV DAC operating in full current-output mode, DC Elite is the zenith of mini USB DAC/amp development. Never has it been better. [See Product Desc. For More] Effortlessly capturing the spectrum from the softest whispers to the most resounding passages, this device shines, no matter how you choose to experience its performance. While it's a breeze to play it back loud, the true test lies in reproducing the nuances of subtle sounds – no mean feat for a mobile device relying on USB's 5-volt power supply. Rather than relying solely on the success of DX320 Max TI in simultaneously adjusting signal and noise levels – an achievement exclusive to analog volume controls – iBasso embraced an even greater challenge with the DC Elite. Maintaining transparency at both low and high volume settings, with an impressive +/-0.1dB channel matching, this iBasso dongle unveils intricacies hidden within the noise floor of your music. The key lies in leveraging the output from ROHM's flagship DAC, receiving pure I2S provided by iBasso's FPGA. Crucially, the DC Elite's BD34301EKV outputs analog in current, as expected of a high-performance circuit. This allows iBasso the flexibility to sculpt the sonic profile to their liking using an extensive current-to-voltage I/V converter. Consequently, DC Elite ensures the highest quality of small-signal from the outset, with any conversion errors presented as a manageable DC offset rather than more sinister total harmonic distortion. The inclusion of powerful op-amp output buffers, supplying 500mA of current, empowers iBasso's DC Elite to promise a high damping factor while maintaining minimal distortion even with low impedances typical of IEMs, Focals, Fostexs and Rosson Audio Designs. Still the closed-loop internal gain remaining after the application of negative feedback around DC Elite's op-amp IC analog circuit remains high. So where she really shines is in swinging voltage, opening up the sound of any high-impedance Audio-Technica, Sennheiser and ZMF Headphones while barely breaking sweat. Multiple DC-to-DC converters and LDOs provide sufficient power and also keep the noise floor down, working hand-in-hand with DC Elite's cutting-edge volume control. So here is Head-Fi's first dongle that can truly say it turns your smart device into a super DAP. Herald the arrival of the first super dongle DAC with DC Elite now, or view the rest of iBasso's releases here or our other DAC/amps here.

--- SOLD! ---HiBy's USB DAC and headphone amplifier built for smartphones, laptops and desktops. ES9281pro DAC Supports MQA HiRes certified 70mW high power Low battery consumption ES9281pro DAC RGB indicator light DSD128 3.5mm headphone jack All metal body  

A 5th Year Anniversary Limited Edition, in the perfect shade of black. HUM made it easy for us when they showed how portable amplification is done. The equation showed to be perfect right angles housing Class-A power, embracing the 4.4 and finished it with the most perfect gold knob you'll enjoy turning to power your favourite headphones without taking up your desk space. It sounds as clean as its lines, its reputation as understated as its size. It's 5-5-5 instead of the usual five-eight-nine, because its the Fifth Anniversary Edition for early-birds who adopt it before 15th of July 2020. === // Good to know:- Audio In/Out: 4.4mm TRRRS Gain Settings: Low Mid High Battery Capacity: 3800mAh@3.8V Battery Life: ~ 8 hours Charging Time: ~ 2 hours Size: 68.5*105*12mm // Further recommendations:-  Customers also choose HUM Tara interconnect to connect to their Digital Audio Player(s) of choice. 

Class A amplification in the most perfect, sleekest form available. Clean, precise presentation with a 4.4mm configuration which makes it instantly pocketable to drive big cans with ease. A favourite amongst customers who are struggling with desk space at home. / Photography by Zepp Crew ---  // Good to know:- Audio In/Out: 4.4mm TRRRS Gain Settings: Low Mid High Battery Capacity: 3800mAh@3.8V Battery Life: ~ 8 hours Charging Time: ~ 2 hours Size: 68.5*105*12mm // Further recommendations:-  Customers also choose HUM Tara interconnect to connect to their Digital Audio Player(s) of choice. 

iBasso Audio can't stop and won't stop loading Cirrus Logic DACs into their sources. DC07 Pro is their latest balanced 4.4mm dongle supplied by a quad of CS43131 DAC chips from the DX180 music player, working controlled by iBasso FPGA-Master technology. It's landed right on Headfonia's Recommended Buys list. DC07 Pro's state-of-the-art decode flows onto a fully-balanced analog path counting on common-mode rejection and claiming 134dB of signal-to-noise ratio. Audiophile-Heaven have added it to their Hall of Fame. To ichos-reviews, it's iBasso's best-ever DAC dongle. An OLED screen basically adds to the illusion of music player levels of detail and fidelity even from USB's 5 volt supply are possible with DC07 Pro. A thoroughly regulated circuit and clean power form the basics here, as with every iBasso. It's solutions like DC07 Pro that continue to see USB DAC/amps raise their game. Further pushing decoding precision is an outboard clock that means DC07 Pro does not rely solely on its USB receiving chip for a master clock, but its FPGA. [See Product Desc. For More] Said FPGA sees DC07 Pro overachieve by supplying its CS43131s DACs the same pure I2S as iBasso's bigger DX180 and DX260 DAP alternatives, pushing down DAC phase noise and jitter for a stable decode. After decoding, iBasso's generous use of negative feedback quashes distortion and claims up to 134dB of signal-to-noise ratio. The employment of this feedback also sees DC07 Pro achieve bandwidth that's effectively flat from 10Hz to 75Khz. That means phase reproduction in the audible human hearing region is perfectly preserved, for the totally realistic portrayal of dynamics and natural transparency – a triumph of iBasso's budget DAC dongle. Powerful op-amp output buffers can supply nearly one watt of power. iBasso's little wonder promises high power and damping factor while maintaining its low distortion into low impedances typical of IEMs, Focals, Fostexs and Rosson Audio Designs. Still the closed-loop internal gain remaining after the application of negative feedback around DC07 Pro's op-amp IC analog circuit remains high. So where she really shines is in swinging volts, opening up the sound of any high-impedance Audio-Technica, Sennheiser and ZMF Headphones while barely breaking sweat. The quality of DC07 Pro's signal will translate to nearly everything you choose to drive from its balanced 4.4mm output, or 3.5mm – turning it into a miniaturised DX180, if you would. Flying the dongle DAC/amp flag high is DC07 Pro, till you turn to iBasso Audio's DC Elite here and other upgrades here, or others in our catalogue here.

Give all your music the DSD treatment, says D16. Built of individual resistors, capacitors and code carried on FPGA-Master 2, this all-to-DSD DAC/amp christened 'Taipan' packs DSP approaching -174dB of THD as iBasso Audio's most original, proprietary piece of work to date. iBasso’s USB-input DAC/amp eschews off-the-shelf DAC chips. D16 doesn't differentiate between CD rips, Hi-Res downloads and Spotify, Tidal or Apple Music streaming. It upconverts all your normal PCM material into DSD before decoding your digital to analog. All formats are passed as DSD through D16’s 1-bit decode. Without irony, D16 will yield the most improvement to collectors of SACD-rip, DSD64 files. As a heavily-upsampling DAC, iBasso take the honours for the first Head-Fi product to target and remove DSD64's terrible ultrasonic noise problems. Twister6 praises "a portable audio solution to deliver flagship-level performance with a neutral sound tuning and a natural analog tonality" before becoming a dynamic duo with PB5. It's landed on Headfonia's Recommended Buys list and in Audiophile-Heaven's Hall of Fame. Its strengths are comprehensively laid out by Headfonics and MOONSTAR Reviews. Buy this as the greatest gift for the SACD collector in your life, then. Following decoding, the pristine analog is kept totally intact by iBasso's now-familiar discrete stepped resistor analog volume control, before D16's Super Class A output stage pushes your flagship earphones and headphones. [See Product Desc. For More] iBasso build a 1-bit DSD DAC into D16 because there's zero error at the point of conversion. There, D16 relies on the total accuracy of DSD's 1-bit conversion to analog, taking advantage of DSD's sheer ease of decoding to boot. The pitch for DSD's 1-bit conversion is digital at its simplest and closest point to analog – level represented only either as a 1 or a 0, switching on or off. To achieve analog, the bitstream is simply low-pass filtered. But there's work D16 needs to do first, preparing incoming DSD and certainly PCM data from your smart devices over USB, coaxial or optical inputs to emerge as the best possible 1-bit digital stream for conversion. How D16 alleviates said white noise issues of DSD64 – indeed, of any inherent problems to single-rate material be it DSD's noise or PCM's steep digital filtering, intersample overs and digital pre-emphasis – is that it applies heavy oversampling to incoming data.  iBasso's DSP oversamples data to huge bit depth and sample rates synchronous to their new FPGA-Master 2 generating I2S. The new multibit data running many times DSD's base 2.8Mhz rate is then put through a Pulse-Width Modulated (PWM) process in preparation for 1-bit decoding.  iBasso treats each of D16's 32 0.1% resistors per DAC phase as individual entities, operating them at very specific moments in the time domain. Ordinarily that might spell chaos co-ordinating a total count of 128 individual DAC elements, but it's iBasso's FPGA-Master 2 that grants a firm grip of how each resistor-capacitor low-pass filter outputs in the time and frequency domain. The result of the entirety of 128 DAC elements outputting at phased intervals leads to a coherent, continuous waveform with finer stairsteps in time. That captures more detail in your music and reduces errors, decoding your music back more accurately to the original waveform. D16's PWM DSP pre-stage addresses the problems of conventional noise-shaped digital's inconsistent rise and fall edges at the frequency level, with adjustments made to facilitate more accurate, predictable switching. This approach results in a reduction of errors by avoiding intersymbol interference. Notably, non-linearities arising from rise and fall mismatches do not manifest as total harmonic distortion. iBasso's PWM DSP does not produce harmonic errors that vary with digital output levels. A digital volume control with large coefficients is also added here to trim levels and add datastream width. This high bit and sample rate headroom is free from overload issues when it is eventually brought back down to the required 1-bit DSD signal for low-pass filtered conversion – but now at a bandwidth of 49Mhz, moving DSD's white noise issues far, far out of the audible band. iBasso's discrete proprietary tech immediately differentiates itself from commercial DAC chips, where IC packages are often too small to perform an ideal 1-bit DSD conversion. D16 also avoids the errors of dynamic element matching inherent to 2-7 bit delta-sigma decoders. The delicate analog voltage waveform painstakingly decoded from DSD in D16 is precious. iBasso's R&D, invested building their own DAC, pays off as the fragile small-signal goes on to be volume adjusted by the same discrete resistor attenuator of DX320 Max TI fame. Said stepped attenuator preserves the resolution of D16 at any listening level. It's that that enables it to play it delicately into your flagship earphones for enjoyment at realistically lower volume levels. Because, it's easy to play it loud, but everyone knows it's in playing back tiny sounds that is the litmus test of a powerhouse capable of outputting as much volume as D16. Without resting on past laurels to increase and decrease both signal and noise levels together at the same time – as only an analog volume control can – iBasso went for the jugular here. After years of work, Head-Fi's analog specialists have once again applied their own, proprietary, stepped analog volume control here to great effect. Transparent at any volume setting down low as much as up high, with virtually perfect +/-0.1dB channel-matching, this iBasso behemoth exposes detail buried deep around the noise floor of your music. So begins D16's fully-balanced, true differential analog circuit that runs at a massive 13 volt operating voltage for linear open-loop operation. Its power stage is fully discrete and boasts buffers capable of outputting more amperes of current than is needed in reality. Said power stage is another call for iBasso's Super Class A to appear. Current mirrors ensure D16's push-pull operation works without crossover distortion, yielding Class A-like performance at all power output levels. That makes for extremely linear open-loop operation before negative feedback is applied ... yet mostly avoids the heat and inefficiency typically associated with Class A designs. Certainly, the quality of D16's power is not discussion, and will reproduce the fidelity of its 1-bit DAC – a milestone in iBasso's history – into your full-sized transducers of choice via your laptop or desktop's USB in your office, or your smartphone on business travels. With superb damping factor as a voltage source, enough standing bias current and signal-to-noise performance to follow today's flagship IEM impedance down low, you know PB5 will be even more in its element pushing TOTL headphones. Everything from Focal to a Fostex and Rosson Audio Designs plus Yamaha and ZMF Headphones is applicable. If you want to free yourself from USB's tether, check out the rest of iBasso's self-contained Android music players here, or view all our other DAC/amps here.

iBasso Audio makes a return to ESS Technology DACs in DC06 Pro, for the better. Their latest balanced 4.4mm dongle runs with dual ES9219C chips – all working controlled by iBasso FPGA-Master technology.  What's special about the ES9219C is that it grants DC06 Pro access to its on-chip analog volume control. MOONSTAR Reviews experienced the "significant upgrade" iBasso offered. This dongle attenuates volume in the analog domain granting much better signal-to-noise performance than the average competitor's lossy digital volume control. Music player levels of detail and fidelity even from USB's 5 volt supply are possible with DC06 Pro. A thoroughly regulated circuit and clean power form the basics here, as with every iBasso. [See Product Desc. For More] Further pushing decoding precision is an outboard clock that means DC06 Pro does not rely solely on its USB receiving chip for a master clock, but its FPGA. Said FPGA sees DC06 Pro overachieve by supplying its ESS DACs the same pure I2S as iBasso's bigger DX180, DX260 and DX320 music players, pushing down DAC phase noise and jitter for a stable decode. After decoding, iBasso's generous use of negative feedback quashes distortion and claims huge signal-to-noise ratio – aided by the analog volume controls of its ES9219Cs. The employment of this feedback also sees DC06 Pro achieve bandwidth that's extended out beyond the human hearing range.  That means phase reproduction in the audible human hearing region is well preserved, for a realistic portrayal of dynamics and natural transparency – a triumph of iBasso's flagship DAC dongle. Powerful op-amp output buffers can supply 100mA of current and mean iBasso's little wonder promises high damping factor while maintaining its low distortion into low impedances typical of IEMs, Focals, Fostexs and Rosson Audio Designs. Still the closed-loop internal gain remaining after the application of negative feedback around DC06 Pro's op-amp IC analog circuit remains high. So where she really shines is in swinging 10 volts, opening up the sound of any high-impedance Audio-Technica, Sennheiser and ZMF Headphones while barely breaking sweat. The quality of DC06 Pro's signal will translate to nearly everything you choose to drive from its balanced 4.4mm output. Flying the dongle DAC/amp flag high is DC06 Pro, till you turn to iBasso Audio's other upgrades here, or others in our catalogue here.

If you think you know how C9II sounds because it's a Class A tube/solid-state hybrid portable amplifier, Cayin Audio asks you to think again. The successor to the genre-defining C9 throws in local feedback adjustment around dual 6P1 Nutubes as well as its discrete solid-state output stage. That’s before anode voltage adjustment allows Cayin to reinvent the rule book, once again. It enters Headfonia's Hall of Fame for that. Twister6 notes this portable behemoth "should last you a long time to enhance any source you pair it up with". In its rawest form – with the barest minimum error correction around its Nutube voltage gain and transistor output stages – C9II is an exercise in circuit purity. It's a simple circuit that outperforms any complex one, especially in portable form factor. With Hyper mode, where operating voltage and bias gets pushed to the linear open-loop maximum, and full balanced differential operation, Cayin equipped C9II with the means to operate at its maximum in every possible mode of operation. [See Product Desc. For More] The vast majority of an amplifier's tuning comes from its initial input and voltage gain stages. Here, we see how far Cayin have come since C9 was released in 2021. A listener's ability to adjust every parameter including tube anode voltage and the feedback loop around Nutubes means up to five potential sonic signatures are possible. The operation of C9II's Gen 5 Nutube circuit in Classic mode reduces negative feedback to a bare minimum, increasing immersion with a simpler and faster circuit that avoids time lag and transient intermodulation distortion. Distortion figures also increase on paper but are of a low-order variety that is less jarring to the ear, compared to the complex intermodulation associated with unabated feedback levels. READ ALSO The full blow-by-blow story of C9II's development Here is where a good old linear open-loop circuit based on immaculate parts gain matching raises the victory flag. And that's before Class A bias and high operating voltages come into play, setting up C9II for success. You can even play with Nutube anode voltage for very audible sonic outcomes.  Throughout, C9II allows linearity specs to remain respectable even without error correction, because there are less errors to correct in the first place. Cayin's biggest asset in that regard comes from differential, balanced operation, where common-mode rejection enters the picture to amplify signal and block off non-linear distortion and noise.  While 6P1 Nutubes are always going to be the star of the show, and adaptable to sonic preferences and tastes, don't ignore C9II's solid-state input either.  Four channels of single-ended Class A Toshiba JFETs work in quasi-complementary fashion. Just NPNs, without PNP mismatches, plus even-order harmonics and square law make for a totally unique differential circuit in a portable set-up. Once you find your ideal match from five possible permutations, the input signal passes through JRC's MUSES 72320 resistor ladder volume controls – kept far away from the input and implemented only after the driver stage to preserve fragile small-signal integrity and excellent signal-to-noise ratio. This preserved resolution is handled all the way by a discrete transistor signal path. C9II's design is more than up to the task of preserving the signal – mere op-amp ICs need not apply. Instead of wasting their input stage advancements by entrusting the analog job to commercial ICs, Cayin's labour of love continued into its discrete, differential, output stage for common-mode rejection. C9II's driver section counts on all the benefits that come with a discrete FET & bipolar design – low open-loop gain and the resultantly lower negative feedback necessary, high slew rates, current-handling and unity gain stability.  Cayin's headphone power amplifier section is inherently stable without going into oscillation caused by too much gain product. The utmost attention is paid throughout. Differentiating itself from even other amplifiers that cling to op-amp layouts seeking THX-certification but with inordinate amounts of gain and feedforward/feedback, C9II's linearity remains excellent already in the open-loop, owing to its high operating voltages and bias. Those ensure individual transistors are working in optimum condition. Distortion and noise are kept low, without resorting to the excessive use of negative feedback. Cayin designed a true-balanced differential amplifier to further improve C9II's linearity, and you can count on common-mode rejection at its best whenever you plug in via 4.4mm preserving its resolution. It's an output stage that's direct-coupled to improve low-frequency performance, and C9II audibly plumbs the lowest bass depths. With the extension down low, phase reproduction in the audible human hearing range for taut, hard-hitting and life-like dynamics is excellent. At the tip of the power stage's spear, large bipolar devices work in parallel emitter-follower configuration to ensure excellent beta and current-handling for good reason, reaping the full benefit of Cayin's quad of 18650 batteries outputting direct DC and working without voltage boost conversion. These power transistors are linear enough in the open-loop, running fully biased and at high operating voltages, that they can be removed from the feedback loop with the push of a button. The reduction in feedback to simple local quantities innocuously just controlling small-signal gain means sound becomes all the more natural. A faster, simpler and more responsive circuit is just able to present musical information in a more effortless way.  Capable of following the impedances of the Empire Ears Raven, Odin and Legend Evo down low, Cayin's tradition building amplifiers that provide actual power as proper voltage sources into halving resistances continues with C9II. This is Cayin's latest exercise in old-school linear amplification brought away from the shackles of heavy hardware and into a portable future – with nary a compromise in sound, and adapted to manage the increasingly complex crossovers flagship IEMs represent. The versatility C9II yields in tuning options is only acknowledgement by Cayin for how much the portable audio market has grown. This Nutube hybrid promises to adapt to and improve your ever-changing transducers and portable sources, making you the chef that is in full control of the flavour of your audiophile nourishment. For much, much more detail into the portable technological advances C9II heralds, check out Cayin's full development story here plus the rest of their gear here, and all our other portable amplifiers here.

HiBy Music have nothing more to prove in the hand, so they've turned their attention to the desk. The Class A FD5 is the answer to the question Head-Fi had – can HiBy build a USB and Bluetooth desktop DAC/amp leashed to a wall power supply that could match, or even exceed, their portable music players? FD5 says they can, and so does Headfonics. Built with a quad of AKM's AK4493SEQs supported by a FPGA, the discrete Class A FD5 is everyone's affordable compact gateway into an over-performing one-box desktop solution. Complete with a power supply given enough space to spread its wings in a separate chassis and finished with voltage regulation throughout, FD5 packs 32 discrete output transistors that achieve output power of over 1.5 watts. [See Product Desc. For More] This is a desktop-calibre HiBy that will drive your Empire Ears Raven, Subtonic Audio Storm or Symphonium Audio Crimson with total confidence from your mobile and computing devices. More importantly, its warm, rich tuning will offer lovely synergy and timeless value with revealing transducers such as Final Audio's D7000, Fostex's TH900 MKII, Canpur's CP74E, Craft Ears Aurum, Elysian Acoustic Labs' Annihilator, PlusSound's Allegro and the Vision Ears Elysium EXT. HiBy's first DAC/amp is not without flagship genes despite being on a budget. It not only borrows its analog stage from the R8II statement DAP. It also goes one better, doubling the output transistor count on FD5 to 32 to handle the abundant current its separate power supply can produce.  With such a discrete output stage HiBy immediately takes a big step ahead of the chasing pack of pedestrian op-amp competitors. Its individual transistors provide the power necessary to push big HIFIMANs and Rosson Audio Designs – not to mention Subtonic's Storm and Symphonium's Crimson – on a budget. Its ability to reel in highly-detailed, exacting and even punishingly revealing gear will, in fact, see it increasingly appreciated down the road. The ability of discrete output devices to handle current and push power is a given, and a necessary HiBy trademark given FD5's power supply sporting several thousand microfarads of filtering capacitors. It's a powerhouse that's escaped the pocket and now has the stage, and the limelight.  At the tip of HiBy's spear, an abundance of 32 output transistors ensure excellent current-handling for good reason, to reap the full benefit of FD5's separate power supply that can draw power from the wall on demand. They can be biased into Class A, if you so choose. Differentiating itself from even other flagships that cling to op-amp layouts seeking THX-certification but with inordinate amounts of gain and feedforward/feedback, HiBy's linearity remains excellent already in the open-loop, owing to its high Class A bias. FD5's quiescent current ensures individual transistors are working in optimum condition. Distortion and noise are kept low, without resorting to the excessive use of negative feedback. The fidelity of four Asahi Kasei Microdevices (AKM) DACs, being fed pristine I2S by HiBy's FPGA and dual clock oscillators, are totally preserved. To build on its impressive, regulated, miniature power supply, HiBy designed a true-balanced differential amplifier to further improve FD5's linearity, and you can count on common-mode rejection at its best whenever you plug in via 4.4mm preserving its resolution. Send this brute power into your transducers directly, or set up FD5 as a hub to also decode digital for a downstream amplifier via separate line outputs around back. It brings convenience too – on top of its USB input, it accepts Bluetooth LDAC feeds too. When you're done with FD5 at the desk move onto HiBy's portable DAPs here, or explore other desktop DAC/amp upgrades here.

Unveiling the GO bar Kensei, iFi Audio's aim for portable audio perfection. Experience the world's first portable DAC with K2HD technology, co-developed by legendary Japanese engineers. This revolutionary tech breathes new life into your music, restoring the warmth and detail lost in digital conversion. Combined with its ultra-portable design and powerful amplification, iFi's Kensei elevates your listening experience anywhere, anytime. It's audiophile-grade sound on-the-go, transforming your commute, workday, or travels into a personal concert. Check out the rest of iFi's gear here, or view our other portable DAC/amps here.

The success of a proof of concept is determined by how long an idea can endure and evolve over time – and iFi Audio's USB-C, battery-powered hip-dac 3 excels in both aspects, marking the third iteration in a long line of portable 4.4mm DAC/amps. 5 ⭐ followed from What Hi-Fi?. Headfonics say hip-dac 3 is the best iteration yet. It went right onto Headfonia's Recommended Buys list. It's top rated on Hifi Pig as well as Audiophile-Heaven, and ichos-reviews praised its timbre. As we move into 2023 and the modern age, the hip-dac 3 introduces USB-C digital input, making it compatible with various phones and cables, offering even greater flexibility for connecting to Apple iPhones, Android devices, tablets, and laptops. [See Product Desc. For More] With its hip-flask size, the hip-dac 3 seamlessly integrates with your devices without compromising its portable sound quality. Its onboard battery not only preserves your source device's power but also ensures a clean and quiet power supply that robustly supports the hip-dac 3's amplifier. Furthermore, iFi's analog volume control consistently maintains a superior signal-to-noise ratio at all listening levels, surpassing conventional digital controls.  The third evolution of iFi's portable powerhouse also reaches a new peak in parts quality. It now incorporates new metal film resistors in the analog stage, and the decoding process, powered by a trademark Burr-Brown DAC, achieves even greater precision thanks to a new low phase noise crystal oscillator. Indeed, hip-dac 3 provides a remarkable taste of high-end audio. Explore the rest of iFi's innovations here, or browse our collection of DACs and amplifiers for more options here.

There's nothing like Enleum's HPA-23RM on the market. As if being one of the only current-source headphone amplifiers on the market isn't enough, HPA-23RM also operates without negative feedback and features a relay-based variable gain volume control in a portable, battery-powered package. Chae Soo-in was never one to design something to please every member of the masses, but the HPA-23RM is possibly the closest he's come to doing so for Head-Fi.  Soundnews handed it their unequivocal Gold Award. "Compaction without sonic degradation is really hard work" said 6Moons but Enleum aced it! Headphone Guru says it packs serious punch driving Susvara. Part-Time Audiophile give it their "highest recommendation" as a Reviewers Choice. The Ear says it's "in a league of its own". hear.audio feels they are well worth their premiums. Enleum's current-source technology infuses musical notes and textures with microdynamic zeal and a charged portrayal, associated with the finest Class A designs. It offers ample extension at the frequency extremes and, at the macrodynamic level, delivers scale and stage. Flat impedance headphones such as HiFiMANs, HEDD Audio's Heddphone 2, the ZMF Headphones Caldera and Final Audio's D7000 will thank Enleum. HPA-23RM is the first resurgence of a current-source amplifier since the days Bakoon International rebranded as Enleum. [See Product Desc. For More] And in addition to the HPA-23RM's current-source output, Chae has designed a completely separate circuit and output that functions as the kind of voltage source found in 99 per cent of other amps, intended for use with your Focals, Fostexs and earphones. In this portable Enleum are therefore two entirely different headphone outputs that allow you to mix and match between what sounds best with your transducers, and act as an empowerer for all your flagship sources. 3.5mm or RCA line-in from any of Cayin Audio's N7 and HiBy Music's RS6 or RS8, for fireworks at your desktop or on your travels. But if you are familiar with Enleum and Bakoon, you'll immediately gravitate toward its specialised trademark: the current-source output on 1/4". While there may be temptations to draw quick and easy comparisons to current-mode amplification found in products like Mass-Kobo and Questyle Audio, Enleum's current-source amplification is entirely unique and mutually contradictory. Working in a way that keeps output current levels constant at all times, even as impedance and voltage fluctuate, the HPA-23RM aims to address a perennial problem – that headphones and earphones induce distortion in amplifiers because they are not simple resistive loads, but rather have complex, frequency-dependent, inductive and capacitive components. However, with the HPA-23RM aiming to eliminate distortion by driving headphones as a constant current source, you experience much greater linearity, hearing an output that faithfully reproduces what was received at the source: the input. Reduction in the effects of backward electromotive force from headphone drivers results in a cleaner sound. With greater linearity and a more accurate final product, negative feedback, typically employed to correct glaring errors, can be eliminated in the HPA-23RM. Enleum's circuit transmits the signal faster and can be kept simpler with far less transient intermodulation distortion arising from feedback. Single-ended operation emphasises even-order harmonics over odd ones, granting a natural portrayal of music that never once sounds artificial. Enleum's JET2 sliding bias scheme intelligently monitors the operating conditions of the discrete devices that make up HPA-23RM's circuit/s, ensuring that transistors operate linearly biased against their current sources in single-ended operation, without generating excessive heat from full Class A. This is a thoughtful addition for a portable product. Listeners can enjoy these innovations with both the current-source and 3.5mm voltage-source outputs on the HPA-23RM. If you aren't into art nouveau and aren't ready to embrace Enleum's current-source output, stick with the conventional voltage-source output that has defined gain amplifiers for nearly all of history. Your ears would certainly benefit from experimenting with either circuit, each completely separate from the other. Some of your gear would certainly thank you, especially those that gravitate towards the low output impedance typical of a voltage source, like Focal's Utopia and IEMs. These transducers also particularly crave a low noise floor. HPA-23RM's precise relay-based discrete resistor volume control provides just that – but not in the way you think. Rather than attenuating signal levels, it's a variable gain volume control that leaves the fragile input signal untouched. Instead, it changes the total amount of gain that's applied to the signal, with only the necessary amount used and never incurring the consequence of detrimental noise from an excess. Variable gain is possible only because HPA-23RM is a zero-feedback design. Enleum's volume control is ideal for preserving the signal-to-noise ratio and the true dynamic range of your music. And a fully-regulated 18650 battery power supply, operating at 1.2MHz, similarly ensures a quiet performance. HPA-23RM is thus a tour de force that demonstrates how mature Enleum has become, offering users abundant choices between two completely different circuits in one chassis – each on par with the other in terms of quality, with only synergy defining your final choice. Look up all of Enleum's gear here, or view our other amplifiers here.

Beat your dongles on the day with Audirect's Atom 3.

Mass-Kobo's choice of current-mode signal has been around as long as Head-Fi has, and the portable, battery-powered, Model 475 calls upon such heritage.  Current-mode amplification eliminates the lag time that might otherwise occur when signal is transmitted in voltage, as it builds up at the capacitances in the circuit – current signal passes through unhindered by comparison, with speed and ease. By doing away with the issue of transmission delay in Model 475, Mass-Kobo virtually eliminates any of the harshness caused by the intermodulation distortion associated with high capacitance, solid-state circuits. [See Product Desc. For More] Model 475 presents music with an iron grip on your transducers, never allowing the slightest note out of control. Any trace of transient smear or note bleed vanishes, from the lowest bass to the highest highs, given the extraordinary damping factor current-mode delivers. Mass-Kobo presents your favourite music with a zeal and vibrancy that's accurate and still entertaining. Another effect of being unhindered by capacitance in the signal path means that huge signal bandwidth is possible, with phase response excellently preserved in the human hearing range for startlingly life-like dynamics, impactful bass and realistic portrayal of musical images.  Indeed, to hear current-mode is to hear a precision to music not encountered before in a conventional circuit, and Mass-Kobo build Model 475 as testament to such a topology. Current-mode technology excels the more it detects a dead short, so Model 475 only works more happily when presented with sub-30ohm loads from Audeze's LCD-5, Dan Clark Audio's Stealth, Expanse and E3, plus HIFIMAN's latest flagship generation. Feed Mass-Kobo only the finest signal. Keep your whole chain working in current-mode with Questyle Audio's CMA18P and M15i. From a player, Cayin Audio's N7 has the consummate sound quality, and more importantly line output stage, necessary to drive Model 465's low-impedance current-mode input stage Meanwhile, browse the rest of Mass-Kobo's range to see what you get higher or on the go here – or view the rest of our amplifiers here.

Lotoo have done it again with PAW S2. The same AKM AK4377 DAC makes another appearance, but S2's platform to perform vastly outstrips its predecessor. [See Product Desc. For More] Trickling down from the superb Lotoo PAW Gold Touch and PAW6000 is the Blackfin DSP chip by Analog Devices. The Blackfin is loaded with code written by Lotoo to present raw I2S for its DAC, sourcing its clock from an AKM PLL chip, so S2's decoding ability goes up significantly. Tidal MQA decoding also arrives as standard. It's absolutely the host with the most (bar Bluetooth) to Twister6. PAW S2's clean, quiet small signal then gets output to a potent 150mW headphone amplifier that outputs in balanced 4.4mm. This little pocket powerhouse leaves you missing little from the full-size experience. Also browse Lotoo's other releases here, or our other portable DAC/amps here.

Ikko Audio's ITM05 music patch won us over with its innovative form factor. If you have been looking at DAC/AMP dongles and adaptors to improve the sound quality on your phone, this patch is what you need for your HiFi on-the-go. // GOOD TO KNOW 2 x CS43198 DAC Chip 3.5mm or 2.5mm Available in black(ready stocks) or white(in October) USB-C or Apple lightning (MFI certified)

iFi Audio's work with ESS Technology DACs continue, with balanced. GO Link Max, their latest balanced 4.4mm dongle, runs with dual ES9219C chips.  What's special about the ES9219C is that it grants GO Link access to its on-chip analog volume control. This dongle attenuates volume in the analog domain granting much better signal-to-noise performance than the average competitor's lossy digital volume control. It receives a full 5⭐ from What Hi-Fi?. Forbes proclaims it the "best headphone DAC" at a budget. Music player levels of detail and fidelity even from USB's 5 volt supply are possible with GO Link Max. A thoroughly regulated circuit and clean power form the basics here, as with every iFi. [See Product Desc. For More] After decoding, iFi's generous use of negative feedback quashes distortion and claims huge signal-to-noise ratio – aided by the analog volume controls of its ES9219Cs. Powerful op-amp output buffers can supply high power and mean iFi's little wonder promises high damping factor while maintaining its low distortion into low impedances typical of IEMs, Focals, Fostexs and Rosson Audio Designs. Still the closed-loop internal gain remaining after the application of negative feedback around GO Link Max's op-amp IC analog circuit remains high. So where she really shines is in swinging voltage, opening up the sound of any high-impedance Audio-Technica, Sennheiser and ZMF Headphones while barely breaking sweat. The quality of GO Link Max's signal will translate to nearly everything you choose to drive from its balanced 4.4mm output. Flying the dongle DAC/amp flag high is GO Link Max, till you turn to iFi's other upgrades here, or others in our catalogue here.

iFi Audio's newest Zen CAN 3 puts flagship technology into an affordable 4.4mm balanced amplifier, merging futuristic xMEMS capability with good old school Class A. Even as we wait on xMEMS to achieve widespread availability, there's so much for the budding audiophile to enjoy with Zen CAN 3. It's a versatile little beast to Headfonia and a complete amplifier for its price to Headfonics. Its maximum power output of 2 whole discrete Class A watts on balanced 4.4mm promises to drive your cans to their maximum potential. [See Product Desc. For More] What is even more impressive about Zen CAN 3, though, is its practicality for listeners of entry-level headphones, right up to easy-to-drive Focal and IEM flagships. iFi's use of their custom 'Operationsverstärker' op-amps means that they're fully in charge of how much – or importantly, how little – gain is applied internally to Zen CAN 3. This mini marvel is capable of working at unity gain at the push of a button. With 0dB of gain applied to the incoming signal, Zen CAN 3 is realistically able to drive 90 per cent of transducers out there, from the easiest to the most difficult, without suffering any noise penalty. It's unlikely users will ever find it necessary to go beyond unity gain on their iFi, allowing listeners to climb up their knob where signal-to-noise can reach a leading 125dB, while always enjoying perfect channel balance. Zen CAN 3's flexibility doesn't stop there. With built-in 'Movie' and 'Gain' modes on top of favourites like XBass and XSpace, all implemented in the analog domain without lossy digital EQ, iFi owners can tweak the Zen CAN 3 to their exact liking. Feed Zen CAN 3 signal from iFi's own Zen DAC 3 and Zen Blue 3, or take hip-dac 3 on the go as you explore the rest of their range here.

Letshuoer make fantastic IEMs and equally ways to listen back to them now. Their latest balanced 4.4mm dongle DT03 runs with dual ES9219C chips. What's special about ESS Technology's mobile DACs is that it grants DT03 access to its on-chip analog volume control.  This dongle attenuates volume in the analog domain granting much better signal-to-noise performance than the average competitor's lossy digital volume control. Further pushing decoding precision is an outboard clock that is located right next to DT03's DACs, pushing down phase noise and jitter for a stable decode. After decoding, DT03 is therefore able to validly claim high signal-to-noise ratio – aided by the analog volume controls of its ES9219Cs. Bring out the best in Letshuoer's IEMs that you can check out here, or view our other DAC/amps here.

Questyle Audio adhere faithfully to current-mode amplification at all form factors, their dedication to this technology extending down to their thumbdrive-sized DAC dongle, the M12i – comes with MFi certification for guaranteed usability with Apple products. It's easy to hear why, if audible results count to you. Operating in current-mode, audio signal gets passed in current instead of the more standard voltage. This eliminates the lag time of the signal that might otherwise occur, as it builds up at the capacitances in the circuit – current signal passes through unhindered as compared to voltage, with speed and ease. [See Product Desc. For More] By doing away with the issue of transmission delay in M12i, Questyle virtually eliminates any of the harshness caused by the intermodulation distortion associated with high capacitance, solid-state circuits. Typical of their high-end offerings, M12i presents detail smoothly and organically without exaggerated warmth or bloat. It easily earned Stereophile's praise for its transparency. Another effect of being unhindered by capacitance in the signal path means that huge signal bandwidth is possible, leading to phase response being accurately preserved in the human hearing range. Indeed, to hear current-mode is to hear a naturalness to music not encountered before in a conventional circuit, and Questyle build M12i as an affordable entry to such a topology. Happily use with any low-impedance device (current signals excel the closer a load is to ground) such as Focal's new line of headphones – Radiance, Celestee and Clear MG – plus Rosson Audio Design and CIEM heavyweights Craft Ears and Empire Ears. Check out Questyle's other gear here, or view our other portable DAC/amps here.