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.

Questyle Audio adhere faithfully to current-mode amplification at all form factors, and building a 4.4mm balanced output into the M15 just extended the capabilities of their flagship dongle. Headfonia says "M15 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 M15 competes on equal terms as music players. Headphonesty hail it as liquid gold. M15 "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 Legend Evo from Empire Ears provides instant synergy, given its 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 M15, 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, M15 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 M15 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 M15'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 CMA15 can further benefit your planar-magnetic headphones at the desk, or browse our other mobile 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 M12.  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 M12, 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, M12 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 M12 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. // GOOD TO KNOW  Current Mode Amplification Smart impedance matching from 8 to 600 Ohms. Ultra low distortion 0.0003% ES9281AC chip (Decodes up to PCM 384kHz/32bit and DSD256) Supports MQA decoding Supports TRRS in-line mic input Gain indicator  Data indicator Compatible with Android 5.0 & above and iPhones (Lightning cable not provided) Dimensions: 5.1 X 1.65 X 0.81 cm Output Power: Built-in smart detection circuit will automatically self-adjust the output power to fit different impedance of headphones. RL=16Ω – Po=46.11mW; RL=32Ω – Po=26.71mW; RL=300Ω – Po=12.26mW; When the detected impedance is less than 70Ω, M12 will self-adjust to low gain output. When it is more than 70Ω, M12 will self-adjust to high gain output. When it is more than 600Ω, M12 will automatically switch to 2Vrms line out. // WHAT'S IN THE BOX:  1 x M12 Mobile Amplifier with DAC 1 x M12 description card 1 x Type-C to USB-A Cable  1 x Type-C to USB-C Cable

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 TraceTogether token. 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". 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.

iFi Audio is ready for its hat-trick, and they've come a long way from playing the long ground since 2019. A series of winners from the ZEN DAC to the hip-dac2, it didn't need the third goal, but why not put it at the back of the net for legacy, applause and hashtag #becauseIcan? [See Product Desc. For More] We would admit our fan art but we refuse to underplay the success of packing in 1,600W or "52x more power" into this tiny solid chassis. Headfonia and Positive Feedback were extremely complimentary, no surprises there. What Hi-Fi? rolled it all together with a 5 ⭐ rating. It also speaks the 2020 language: 4.4mm. We hope you're ready to stack. This stamp-sized marvel designed with the help of Hi-Fi legend John Curl of Parasound fame is worth accommodating.

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.

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.

ESS Technology DAC chips debut here in an iBasso Audio USB-C DAC/amp dongle, and boy does it show in the way the 3.5mm DC05 sounds. Plenty more involvement and detail shows in the way this dual ES9219C dongle that plays Tidal MQA sounds, reminiscent in more ways than one of the flagship DX240 music player. Headfonia consider DC05 a "very serious option", and Headfonics add it has everything for a 3.5mm DAC/amp. This iBasso made its way into Audiophile-Heaven's Hall of Fame. To turn your Android, iPad or other mobile device into something mimicking iBasso's reference DAP is no mean feat, but hearing is believing. Enjoy lots of involvement through the mid-range in particular where the majority of your music lies, though that doesn't detract from plenty of presence still in the lows and highs.  Drive your favourite earphones and headphones alike through DC05, or browse iBasso's other offerings here and our other DAC/amps here.

Cayin Audio's famed amplification packs up to join you back on the road with the launch of C9, featuring 4.4mm and 3.5mm inputs and outputs. Headfonics praise it to the roof as it "revitalises tubes on the go, a traditional niche in our hobby that seems to be forgotten", going on to name it Best Portable Amp of 2021. This battery-powered, tube and solid-state hybrid lands in time for use on your office desks and in hotel rooms, establishing your reference headphone listening anywhere you so choose. [See Product Desc. For More] C9 is a fully-balanced, truly differential amplifier built upon the essentials establishing a device as basically thoroughly engineered. READ ALSO The full blow-by-blow story of C9's technical innovations A high operating voltage of more than eight volts and a reliance on discrete parts for over 90 per cent of the design means C9 is not only capable of putting out over 4 watts per channel, but also ensuring it is the cleanest, most linear kind of signal possible. Achieving 125dB of signal-to-noise ratio would not have been otherwise possible in a discrete design, with all the benefits that brings, without exacting layout. The input section exists on the popular Nutube. C9's dual timbre circuit revolves around two of Korg's fluorescent triodes or toggled solid-state FETs, the philosophical transistor alternative. READ ALSO C9 blurs the line with desktop amplifiers The delicate input signal is then passed to a discrete solid-state output stage that can be switched between working in pure Class A mode or Class AB. Built with individual transistors of Cayin's choosing allows great control over tuning and an innately linear open-loop circuit, with minimal negative feedback, to be fashioned, while producing genuine current for demanding headphone loads. C9 is a brute in ballet shoes, confirmed by the big volume pot controlling dual precise MUSES resistor ladder attenuator parts occurring after the driver stage, kept far from the input signal for maximum integrity.  Line outputs from Cayin's own N7, HiBy Music's R6III plus R2R RS6, and iBasso Audio's DX320 will never be better pampered than via C9. Use it in a mobile stack acting as the platform for Hedd's HEDDphone® – absolutely recommended, says Ear Fidelity – MYSPHERE 3.2, Rosson Audio Designs, plus almost any ABYSS or HIFIMAN, to shine. "And while DAPs come and go", Twister6 believes "C9 should last you a while to enhance any source you pair it up with". Headfonia say it "should really be the first amp to look at to get four completely different sound signatures that's simply impressive". See how Cayin's design chops translate to their desktop amplifier offerings here, or view our other DAC and amplifier offerings 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.

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. 

The mobile revolution continues as driven by iBasso Audio. DC06 is their latest balanced 4.4mm dongle supplied by dual ESS Technology ES9219C DAC chips, with analog volume control aboard. iBasso claim 123dB of signal-to-noise ratio as a result, for music player levels of detail and fidelity even from USB's 5 volt supply. It's solutions like DC06 that continue to see USB DAC/amps raise their game. Headfonia praise DC06 as "something really catchy ... a possible must-have". Headfonics confirm it does it all. Audiophile-Heaven recommend it for "a super natural, clean sound with excellent staging and instrument separation". [See Product Desc. For More] Further pushing decoding precision is an outboard clock that means DC06 does not rely solely on its USB receiving chip for a master clock. iBasso derive a clean clock signal via PLL, pushing down phase noise and reducing jitter even at this form factor. DC06 also decodes 16X MQA, to boot. Pure, clean analog is therefore derived from your mobile sources, and this pristine little dongle DAC isn't afraid to push big cans either – promising up to 320 milliwatts from its 4.4mm output. The DC06 platform comes with a detachable cable and can be adapted for a range of mobile applications, from smartphones to iOS Lightning and laptops. Also browse the rest of iBasso's options here, or our other DAC/amps here.

iFi Audio have left their mark on Head-Fi since the very beginning and what better product for them to leave their Signature on than the iDSD. Their most potent DAC/amp product has been powering our listening on the go for the decade that's gone before, and iDSD Signature now gets a refresh with a new 4.4mm output capable of pushing over 4 watts. [See Product Desc. For More] This power meets precision, balancing just the right tinge of warmth to add emotion to a detailed and airy tuning that is faithful to the recording. This handy devices takes a USB input from your PC or your computer, and puts traditional iFi know-how at your service. Among the smallest portable products that come direct coupled input to output, iDSD Signature is ready to set a standard at any level. It's already drawn praise on Headfonia for its versatility, power and transparency, easily making its way onto the 'Recommended Components' list there. Headfonics add it's "a fun machine capable of driving practically every headphone out there while at the same time remaining highly musical" and named it Best Portable DAC/Amp of 2021. The Audio Beatnik wraps it up nicely, how close iDSD Signature gets you to the performance of full-size desktop components. View the rest of iFi's line here, or check out our other DAC/amp 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. 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 D8000 Pro 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.

The mobile revolution continues as driven by iBasso Audio. DC04 Pro is their latest balanced 4.4mm dongle supplied by the dual Cirrus Logic CS43131 DAC chips from the DX170 music player, working controlled by iBasso FPGA-Master technology. It's a Headfonia Recommended Buy, and it ticks all the boxes as a complete solution to Audiophile-Heaven. iBasso's flagship dongle is one of 2023's best to eCoustics. It represents the progress dongles have made to ichos-reviews and MOONSTAR Reviews. DC04 Pro's state-of-the-art decode flows onto a fully-balanced analog path counting on common-mode rejection and claiming 131dB of signal-to-noise ratio. Music player levels of detail and fidelity even from USB's 5 volt supply are possible with DC04 Pro. A thoroughly regulated circuit and clean power form the basics here, as with every iBasso. It's solutions like DC04 Pro that continue to see USB DAC/amps raise their game. Further pushing decoding precision is an outboard clock that means DC04 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 DC04 Pro overachieve by supplying its CS43131s DACs the same pure I2S as iBasso's bigger DX170, DX240 and DX320 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 131dB of signal-to-noise ratio. The employment of this feedback also sees DC04 Pro achieve bandwidth that's extended from 20Hz to 40Khz. 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 DC04 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 DC04 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 DX170, if you would. Flying the dongle DAC/amp flag high is DC04 Pro, till you turn to iBasso Audio's other upgrades here, or others in our catalogue 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)

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.  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.

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. 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 DX170, DX240 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.

Below iDSD Diablo 2's futuristic exterior and the promise of new, wonderful technologies like xMEMS and wireless Bluetooth 5.4 aptX™ Lossless input is a tried-and-true iFi Audio product that is ready to deliver – today. The heights the proven platform that was the origin