iFi audio iDSD Diablo

General Information

iFi ushers in the New Year with the best battery-powered DAC/headphone amp the company has ever produced – the devilishly brilliant iDSD Diablo. Engineered to sit proudly at the top of iFi’s illustrious range of mobile and transportable devices, the Diablo is built for the purists – the true headphone enthusiasts who crave pure, unadulterated sonic performance.

With dimensions of 166x72x25mm, its size is similar to DAC/amps in iFi’s long-running, transportable micro iDSD series, with a built-in, quick-charge-compatible battery that makes it easy to move from desk to living room to travel bag. Its sleek new design and fiery red finish, however, mark it out as distinctly different.

Like a high-performance sports car designed for uncompromising speed, the iDSD Diablo sets aside facilities offered by other iFi DAC/headphone amps – sonic tailoring options and Bluetooth connectivity, for example – to focus on pure sonic power, featuring ultra-high-quality circuit components and the ability to drive any headphones on the planet with aplomb. Simply connect your digital source via USB or S/PDIF, plug in your headphones and prepare for a riveting musical ride from this elite-class digital audio engine, expertly tuned to achieve captivating speed, scale and dynamic range.

DAC’s entertainment

The iDSD Diablo’s digital stage incorporates a Burr-Brown DAC chip that iFi uses extensively, selected for its natural-sounding ‘musicality’ and True Native architecture. Here, two of these chips are installed in a custom ‘interleaved’ configuration – this enables four pairs of differential signals (two pairs per channel) which lowers the noise floor, improves channel separation and enhances the DAC’s ability to resolve fine musical detail and micro-dynamics.

iFi’s experience with this Burr-Brown chipset means it knows how to make the most of it, but the creation of an exemplary digital stage involves more than the selection of a particular DAC chip. One such critical component is the XMOS chip that processes the audio data received via the USB and S/PDIF digital inputs. The iDSD Diablo uses a new low-latency XMOS microcontroller with greatly enhanced processing power – compared to the current generation of eight-core chips, this new 16-core IC delivers double the clock speed (2000MIPS) and four times the memory.

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iFi’s in-house digital development team has programmed the XMOS firmware to optimise sound quality and ensure a perfect partnership with the DAC circuitry. Extensive jitter-eradication technologies are also applied to the digital stage, including an enhanced version of iFi’s GMT (Global Master Timing) femto-precision clock featuring a new crystal oscillator.

Every music format at the highest quality

Hi-res audio support is state-of-the-art, handling PCM data to 32-bit/768kHz, all levels of DSD up to DSD512, and single- and double-speed DXD.

Thanks to the Burr-Brown DAC chip’s four-channel True Native design, PCM and DSD take separate pathways – this enables DSD, as well as PCM, to remain ‘bit-perfect’ in its native form right through to analogue conversion. This is often not the case with DAC devices from other brands – even if DSD compatibility is stated, many such DACs convert DSD signals to PCM.

MQA – the hi-res streaming codec, as used by Tidal’s ‘Masters’ tier – is also supported through the USB and S/PDIF inputs, with full decoding of MQA files up to 384kHz thanks to the processing power of the new 16-core XMOS chip. This means that the full ‘three unfold’ decoding process is performed internally, as opposed to only the final unfold in the manner of an MQA ‘renderer’. Globally, MQA has become an important consideration for any comprehensively equipped DAC; for Tidal Masters subscribers, the iDSD Diablo is a great way to make the most of the superior sound of which this streaming service is capable.

PureWave – balanced circuit design for the purest sound

The digital stage is only half the story in any DAC/headphone amp; when it comes to the crucial analogue circuitry, many such devices fall short. Balanced, differential analogue circuit design has long been championed for its ability to reduce noise and cross-talk within the signal path by fully separating the left and right channels. However, this is more complex and costly than single-ended circuitry, and so has traditionally remained the preserve of high-end hi-fi components.

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iFi has gradually introduced fully balanced circuit design across its range – first in the flagship Pro Series components, then in the entry-level ZEN Series devices. The company’s two newest DACs, the mains-powered NEO iDSD and transportable iDSD Diablo, benefit from further refinement of their balanced, symmetrical dual-mono topologies with short, direct signal paths. iFi calls this circuit concept ‘PureWave’, referring to the sonic purity it achieves thanks to exceptional linearity and infinitesimally low levels of noise and distortion.

Powerful amplification delivers musical gratification

Already renowned for the performance of the amp stages in its DAC/headphone amps, iFi has ensured the iDSD Diablo is its best-ever transportable amplifier, designed to deliver reference-level sound. Able to drive all manner of headphones with ease, from highly sensitive in-ear monitors to current-hungry planar headphones, it delivers prodigious power (up to 5000mW), propulsive energy and engaging dynamics, coupled to a remarkable ability to resolve fine texture and detail.

The great variation in the electrical characteristics of different headphone/earphone types is accommodated by the provision of three settings enabling the user to adjust power and gain to suit whatever the amp stage is tasked with driving: ‘Turbo’ ramps up the level of drive for current-hungry headphones, ‘Eco’ dials down the power to suit high-sensitivity in-ear monitors and/or extend battery life, and ‘Normal’ sits between the two.


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High-quality components are used throughout the iDSD Diablo’s circuitry, utilising its larger form factor in comparison to smaller, pocket-sized DAC/amps. Custom ultra-low-distortion MOSFET op-amps feature in both the digital and analogue stages, together with a hand-selected range of capacitors including the multilayer ceramic type TDK C0G and aluminium-polymer type Panasonic OS-CON. MELF thin-film resistors and inductors from Taiyo Yuden and Murata also feature in the circuit design.

These are all more costly than commonly used circuit components, but class-leading qualities such as low ESR (Equivalent Series Resistance), high stability and low distortion pay great dividends in terms of sound quality. Many hours of listening tests, alongside rigorous analysis in the lab, has determined the optimum circuit design to deliver maximum musical enjoyment.

An important aspect of the iDSD Diablo’s circuit design is its direct-coupled nature (no coupling capacitor is present), achieved without a conventionally applied DC servo; iFi calls this design Servoless Direct Drive. Also important is the use of a high-quality analogue potentiometer to control volume – its sonic transparency compared to chip-based volume controls makes the most of the clarity and resolution of the amp stage.

OptimaLoop – negative feedback that is purely positive

‘Negative feedback’ is used in amplifier circuits to compare the output signal with the input signal and correct errors, in order to control gain and reduce distortion. For sound quality, this is positive; but commonly applied, one-size-fits-all ‘global negative feedback’ can highlight different problems whilst solving others – corruption of the error signal, phase shifts, group delay and so on can all have a negative impact on sound quality.

Recognising that different parts of a circuit benefit from specifically optimised feedback loops, iFi has developed a negative feedback system that is much more accurate than the usual approach. This incorporates multiple feedback paths instead of one global loop, each path optimised for a particular function and working synergistically with the others to deliver optimal overall performance. iFi calls this new configuration OptimaLoop.

This power does not corrupt

In keeping with the iDSD Diablo’s focus on pure, unadulterated performance, much attention has been applied to the power supply circuity. Battery power provides a theoretical performance advantage over mains power, with ultra-clean and stable DC current avoiding the issues that can be introduced by mains electricity with its dips, spikes and noise-inducing RFI/EMI pollution. There are also potential sonic downsides to battery power, however, resulting from low output voltage and inconsistent output impedance as batteries discharge – these issues are fully tackled by the iDSD Diablo’s design.

In order to make less efficient headphone types sing – planar magnetic designs, for example – the voltage needs to be stepped up from 3.7V to +/- 15V. This is achieved through the use of a step-up converter running at 1.2MHz – a frequency far beyond audibility that is easier to filter than a typical switch-mode supply, enabling high linearity and ultra-low noise.

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High-bandwidth power supply circuity is dedicated to each critical part of the iDSD Diablo’s design, with independent linear regulation delivering excellent PSRR (Power Supply Rejection Ratio) performance. The headphone amp stage eschews IC regulators in favour of Panasonic OS-CON capacitors, delivering 2320uF between them. The DAC section benefits from an ultra-low-noise regulator with additional passive filtering, reducing high order harmonic distortion and, in turn, jitter. Even the USB input stage benefits from dedicated regulation and multistage filtering, and the microprocessor control circuitry (often a local source of digital noise) has separate regulation, too.

Get connected

At the front of the unit, alongside a standard 6.3mm single-ended headphone socket, resides a 4.4mm Pentaconn output for headphones offering balanced connection. An increasing number of high-quality headphones and in-ear monitors either come so equipped or give the option of detaching the cable and upgrading to a 4.4mm Pentaconn connector (this output is particularly recommended for tougher headphone loads). In terms of power, the balanced headphone output delivers 12.6V/4980mW into 32 ohms and 19.2V/611mW into 600 ohms, while the single-ended output supplies 8.8V/2417mW into 32 ohms and 9.6V/153mW into 600 ohms.

At the back of the chassis are two digital audio inputs: USB-A and an S/PDIF socket that accepts both electrical and optical signals, the former via a 3.5mm connector and the latter via a supplied adapter. Unusually, the USB-A input features a ‘male’ connector, rather than a typical ‘female’ port – this arrangement provides greater mechanical integrity than the USB/Micro USB ports commonly used by other DAC/headphone amps. It also offers an advantage to users of iPhones and iPads with Lightning ports, because it accepts Apple’s Lightning to USB Camera Adapter directly without requiring an additional female-to-male USB adaptor. A separate USB-C charging port is also provided, along with a fixed line-level 4.4mm Pentaconn balanced output to connect an external amp.

A package worthy of reference status

In keeping with a reference-level product, iFi has been generous with the accessories supplied with the iDSD Diablo. The DAC/amp may be powered from the mains, as well as by its built-in battery; in order to ensure optimal sound quality when hooked up to the mains, iFi includes its iPower 5V AC/DC adapter, which engenders significantly less noise than other similar devices thanks to Active Noise Cancellation and sells separately for £49.

Also included is a 4.4mm Pentaconn to XLR balanced interconnect cable, enabling the iDSD Diablo to be connected to an amp and speakers (or a pair of active speakers) with balanced XLR inputs. Other supplied connectors include a short (15cm) USB-C to USB-A audio cable, as well as an extension cable – all USB3.0 compliant – plus a USB-C charging cable and an adapter to connect headphones with a 3.5mm jack to the 6.3mm single-ended output. Even a travel case is included.

In addition, the first iDSD Diablo production run includes iFi’s iPurifier3 in the bundle – retailing separately at £129, this USB ‘noise-buster’ is designed to tackle all aspects that degrade sound quality over USB thanks to a precision mix of tech including Active Noise Cancellation. It all adds up to a package of accessories worth around £300.

Delivering devilishly good sound for headphone lovers, iFi’s iDSD Diablo is available from selected retailers from Friday 15th January at an RRP of £899, (€999, $899).

Latest reviews

HansBarbarossa

100+ Head-Fier
iFi iDSD Diablo: devilish charm
Pros: SOUND, design, functionality, super kit.
Cons: No (if you leave the price out of brackets)
Hi friends!
The New Year holidays have flown by, but I want to share with you my review, I posted on my site in April 2021. Moreover, my admiration for using this audio device has only grown stronger.
I will have to shorten my review a little when translating from Russian into English, but I hope that I will be able to convey all the main information and my emotions to you in this form.

So, see the scarlet glow flooding the sky, listen to the menacing thunder - the iFi iDSD Diablo appears on the scene!




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Text: Alexey Kashirskey (aka Hans Barbarossa / audio-ph.ru)


Specifications
DAC chips: 2 x Texas Instruments Burr-Brown DSD1793 (Bit-Perfect Burr Brown DSD, DXD, PCM)
Digital Inputs USB 3.0 type A (USB 2.0 compatible)
SPDIF 3.5mm Coaxial or Optical
Formats supported DSD512 / 256 /128 /64
Octa/Quad/Double/Single Speed DSD
DXD Double or Single Speed 768/705.6/384/352.8kHz
PCM 768/705.6/384/352.8/192/176.4/ 96/88.2/48/44.1kHz
Frequency Response 10Hz – 80kHz +/- 3db
SNR Balanced -120db / SE -114db
Dynamic Range Balanced – 120db / SE 114db
THD + N Balanced 0.002% / Se 0.001%
Headphone Max Output Balanced 19.2V 4,980mW @32 ohms / 12.6 V 611mW @ 600 ohms
SE 8.8V 2,417mW @ 32 ohms / 9.6V 153mW @600 ohms
Fixed Audio Output 4.4 Balanced
Power Consumption Turbo 12w / Normal 5w / Eco 2w
Charging via USB type C BC V1.2 up to 1900mA
Ipower 12v adapter included
Battery Lithium Polymer 4800mAH
Dimensions 166x72x25mm / 6.5”x2.8”x1.0”
Weight 330g / 0.73lbs



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Appearance and kit

The device comes in a presentable white box, the upper part of which is a printing wrapper. On its front side is our stunning scarlet "devil", above it is the logo of the "iFi" brand, below the model name with a sticker reporting full support for the progressive MQA format, as well as a detailed list of device features: USB DAC Headamp, Octa-speed DSD512 / PCM 32bit/768kHz, MQ/Fully balanced 4.4mm output. If this is not enough for someone, then a complete list of characteristics can be found on the back of the package. Everything, as always, with iFi is stylish, strict, concise and neat.


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With lust, we open the box and take out the iDSD Diablo from it, and with it all the necessary accessories: iFi iPower power adapter with an adapter to USB type-C, a blue 3.0 type-A male/female cable for connecting the device to a PC, a short connecting cable type-A / type-C, interconnect cable for balanced iFi 4.4mm / XLR connection to an active speaker system or amplifier with appropriate connectors, 6.3 / 3.5mm adapters and 3.5mm optical. And all this goodness lies in an excellent branded iFi iTraveller bag for carrying the device (it costs $49 separately).


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It turns out that the set is five-star, "All inclusive", you don't even know what else to want. There is everything and even more! But let's not dwell on this for a long time, but go directly to the acquaintance with our ward.

Oh, how hard it is to resist the pleasure of describing our "audio devil", because the level of delight that it causes is really comparable to the emotions of getting to know the legendary Lamborghini Diablo. What is this if not a sports car in portable audio?! The seamless case of red color with rounded side edges, as well as the front and rear panels, is made of metal. The build quality does not cause the slightest criticism: everything is fitted tightly, without gaps and backlashes. The device is 166mm long, 72mm wide, 25mm high and weighs 330 grams.

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On the front panel of the iDSD Diablo there are 6.3 mm (SE) and balanced (Pentacon) 4.4 mm headphone outputs, a three-position “gain” switch (Ecco / Normal / Turbo), an indicator that signals us on or off device, as well as the sampling rate of the playback format is displayed here in different colors:
Yellow: PCM44/48/88/96kHz
Cyan: PCM176/192/352kHz
White: PCM768kHz
Magenta: DSD64/DSD128/OFS
Red: DSD256/DSD512
Green: MQA
Blue: MQA Studio


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The volume control completes the whole thing with an extremely smooth ride, which, in combination, is also an on / off toggle switch for the device.

On the rear panel we find an S / PDIF input (combined coaxial / optical), a balanced (4.4 mm) line output, an input for a USB type-C charger and a digital USB input for connecting the device to a PC or smartphone (Android requires an OTG adapter /for iOS Lightning Audio).

On the underside of the device, in the corners, there are four round silicone feet.


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When connecting the device to a computer, it is recommended to go to the manufacturer's website and install the appropriate USB audio (ASIO) driver. The driver downloads and installs quickly. After installing the driver, an icon with the iFi brand logo appears in the tray and the system automatically finds the iDSD Diablo. If you, like me, use the foobar 2000 software player, go to preference / output and select the device we need from the list.

My scenario for using the device is as follows: xDuoo x10t II digital transport via S/PDIF (optical, coaxial), Huawei p20 pro smartphone (USB) using the UAPP or Hiby Music software player (when additional volume adjustment is needed), PC via USB with foobar2000 player (Asio iFi driver). In all cases listed, there were no problems. Everything is fast and clear.
Well, now there is also a wonderful opportunity to output an analog signal through a balanced connection to active studio monitors or an amplifier using the supplied 4.4 mm/XLR cable. Predecessors, in the face of micro iDSD, iDSD BL and Signature, for their part, offer a standard line output in the form of a 2-RCA connection. But, perhaps, for most users, this method will be even more convenient.


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The heart of the iDSD Diablo is Burr-Brown's "True Native" DAC chip, which the company uses extensively in its devices. Two DSD1793 chips are installed here in a special "interleaved" configuration - this allows the use of four pairs of differential signals (two pairs per channel), which reduces the noise floor, improves channel separation and increases the DAC's ability to accurately, accurately and dynamically transmit the audio material being listened to.

In general, there are a lot of interesting technical innovations in the device, if you wish, you can read about them on the manufacturer's website, and it's time for us to move on to the main part of our review, to the innermost essence of this red dac/amp - its incomparable sound!


Sound Impressions

Before listening, the device was burn-in for approximately 100 hours.

The following IEMs/Headphones were used for listening: Beyerdynamic DT250/250, Hifiman HE-4, Phonon SMB-02, Phonon 4400, Softears RS10 и RSV, FIR Audio M5, VxV и M4, 64 AUDIO A12t и A18, Jomo HAKA, Vision Ears VE8, EVE20 и VE4.2, InEar ProMission X & ProPhile 8.


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Listening took place mainly through the 6.3/3.5 mm output, with the exception of the IEM FIR VxV model, which was connected to both the regular 6.3/3.5 mm and the balanced output.
Digital signal sources: Asus vivobook pro laptop via QED Performance USB Graphite + iPurifier 3 cable, Huawei P20 Pro smartphone + USB Audio Player PRO, xDuoo X10t II portable digital transport.

iFi iDSD Diablo perfectly coped with low-impedance sensitive in-ear headphones, high-impedance full-size models, and easily rocked the rather "tight" planar Hifiman HE-4. No noise or distortion was noticed, the gain was mainly used in the modes: Ecco/Normal.


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When connecting sensitive low-resistance IEM/CIEM to the Diablo, be extremely vigilant. Even in Ecco mode, after turning on the device, keep the volume control in the zero position and add the level as carefully as possible, literally millimeter by millimeter. Most IEM/CIEM need only 2-5 millimeters of rotation, then the signal will be redundant.

And a few more recommendations. At home, when connecting the device to a PC, additionally adjust the volume with a software player. On a smartphone/tablet, use, for example, HiBy Music (it has the ability to adjust the digital signal). Also a good option is to use a proprietary iFi iEMatch adapter (sold separately). This adapter automatically expands the use of this earpiece, allowing it to be paired with the most sensitive in-ear headphones, adding two more levels of “Gain” signal adjustment to it.

Well, now, finally, we go directly to listening.


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From the very first minutes of meeting Diablo demonstrates an extremely adult approach to sound production. In fact, this is the voice of a serious desktop or even a stationary audio device.

The device delivers the material accurately, massively, scrupulously, outlining every nuance of the composition being listened to, with amazing dynamics, detailing, excellent pressure and good separation of plans. Speed, attack, rise and fall of sound - everything here is at a very high level.
Every pinch, reverb, powerful and biting hit - iDSD Diablo works out as accurately and reliably as possible. The device also boasts a harmonious and proportionate study of micro and macro nuances, as well as a wide dynamic range. At the same time, the device does not "shrink", but transmits the audio material densely, richly, filling the sound images with a living, "bodily" substance.

This is a very well balanced, timbre rich, multifaceted and extremely naturalistic manner of sound delivery. Without exaggeration, this Diablo is damn good!


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iFi iDSD Diablo does not embellish the audio material, but gives it the way it is: neutral, honest, wide and contrasty, allowing you to show your "voice" and open up in all its glory with almost any headphones, transmitting the sound extremely accurately and reliably. The device itself has a neutral sound with an almost linear frequency response.

There are no peaks or dips, as there is no sharpness and distortion. Everything is clear and to the point. Diablo, as a pleasant intelligent interlocutor, tells his story competently, with feeling, sensibly, with placement, with the right emotional intonation and correct gestures.

Overall, this is a clean, extremely dynamic, smooth and natural manner, delivered in a slightly warm, analog form.


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Lows sound extremely accurate and powerful. If your headphones are able to "blow out" the fullness of the bottoms, then rest assured, Diablo will shock your ears with a powerful subbass response and accurate bass relief.
There is both a clear clap with a tight beat, and a powerful, agile bass. At the same time, the register is fed cleanly, smoothly, without excessive pumping and daubing. Monumental, accurate and reliable, with a well-defined impact force.
Drum rolls roll out on both sides of the listener, and the mid-bass area is delivered evenly, lively, quite correctly and reliably.


Mid frequencies are served distinctly, in detail, comfortably and unusually melodic. Musical images are drawn large, bold and tangible. The middle is plentiful and "venerable", without the slightest hint of falsity and distortion. This is a well-balanced, harmonious and at the same time emotional performance, where all the elements of the composition are presented with extraordinary accuracy, large and multifaceted, with amazing smoothness and informativeness.
String instruments, wind instruments and piano sound gracefully, unusually clean and expressive.
Every sound and audio image transmitted by the device is polished like sea pebbles. Vocal parts are transmitted unusually deep, noble and harmonious. Male and female voices are displayed in relief, dense and naturalistic. Here, every musical image is endowed with its tangible basis.


High frequencies do not excite the ear with excessive harshness, they are transmitted in a neutral manner - very accurately, in detail and legibly, with good articulation, and enviable correctness.
It is clean, smooth and comfortable. There is no excessive brightness here, but there is an excellent development of this register and a natural, extremely musical sound without sharpness and distortion.


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In terms of sound, Diablo, as in the case of appearance, causes a wow effect, everything is so flawless, clear and to the point. He also has no weak points in terms of genre preferences. "Red audio-devil" can handle everything: classical music, instrumental, jazz, electronics, rock and all kinds of brutal genres.

Again, I can not resist the high syllable, because the sound of Diablo definitely deserves it. You want to dive into this musical river with clean and cool water made of harmonies and notes, splash there and then swim downstream towards the huge ocean, in which all the songs of the world pulsate!


Conclusion

iFi iDSD Diablo is an excellent audio device. Everything is wonderful in it: from a rich set, design, implementation of the technical part, to the main thing - sound.
It is a luxurious, complete, uncompromising device, harmonious and wonderfully balanced throughout. Such a pumped portable can be safely considered as a solution for a variety of tasks and support for various types of headphones, up to the most demanding models.

Well, about the cost of our today's hero. At the time of writing, the suggested retail price for the iFi iDSD Diablo was $999.00.
Sure, the price tag is a little sobering, but that's what high-end original sound is worth, whether we like it or not. Although, looking at the pricing of audio devices from other brands, such a price seems to be quite low.
In general, if you have the opportunity to fork out for a great sound, then I recommend the iFi iDSD Diablo without the slightest hesitation.

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Dixter
Dixter
Nice review... you did great.... as much as I like the output on single ended the 4.4 balanced output is where the magic is for my headphones... the Diablo is amazing for its size... and has plenty of power... even drives my Hifiman He6se V2 quite well...

ufospls2

Headphoneus Supremus
iDSD Signature vs iDSD Diablo
Pros: Transportable
Sound quality over Black Label
Cons: Separate Power and Data lines, personal preference.
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Head to Head
Hi Guys,

Today we are having a look at not one, but two interesting pieces of gear. The iFi iDSD Signature, and the iDSD Diablo. The Signature is essentially a refined version of one of my favourite bits of gear, the previous iDSD Black Label. The iDSD Diablo is an all new model, aimed at being their best transportable iDSD product yet! How did they fare? Lets find out. (From here on out, I will refer to the iDSD Signature as the “Sig” and the iDSD Diablo as the “Diablo.”)

The iDSD Black Label was my favourite piece of transportable source equipment I had owned or used. It was fairly affordable, packed with features, and powerful. The Sig. has improved upon the BL in all areas in my opinion. The layout makes more sense and is less “fiddly” than the BL, it has a tiny bit more power, and features iFi’s “S Balanced” circuitry. This circuitry is said to deliver the benefits of balanced connections, to those with single ended topology. Now, I’m not on board with balanced being better ALL the time, I think a good single ended piece of gear will beat a poor balanced piece of gear, and vice versa. However, in this instance, the Sig does sound slightly more refined than the previous BL. New on both the Sig and Diablo is the 4.4mm Pentaconn output, which is a welcome feature as more and more manufacturers are using this standard nowadays.

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Front View
The Sig features many of the things that the BL did. It has the XBASS feature, and the 3D crossfeed feature. It feature iFi’s IEMatch, as well as low, medium, and high gain settings. This, combined with the 100mw more power with 4100mw at 16ohms, means that the Sig can drive most headphones very well. From hard to drive planer magnetics, to very sensitive IEMs, the Sig has you covered. In addition to the 1/4” and 4.4mm outputs on the front, the Sig also has RCA outputs on the rear, as well as a 3.5mm combo SPDIF/Optical input for those who would rather not use USB as their data connection. One thing that has changed, and it is the only thing I actively prefer on the BL, is the separation of the Data and Power inputs. On the BL, it was very simple, one USB input dealt with both Data and Power, with the option to use the SPDIF input for data if you would prefer. On both the Sig and Diablo, the Data and Power inputs have been separated. Now, this does bring sonic benefits in terms of there being less noise from the power being picked up by the data line, and ending up in whatever you are listening to. However, if you want to use the Sig or Diablo off of mains power, and not their battery, you now need to make sure they are plugged into something like iFi’s 5v iPOWER adapter, or run two usb cables from your computer. This isn’t the end of the world by any means, but I found it a bit frustrating at times, and not as user friendly as the BL. Perhaps it would have been wise to separate the power and data inputs on the Diablo, as it is shooting for “ultimate” sound quality, but leave it as it was on the Sig, as that is a more “all round” type of device.

In terms of sonic performance, I found the Sig to be very similar to its predecessor, with slight refinements. In terms of tonal balance, it is mostly the same, neutral verging on slightly warm. Decent detail retrieval, both macro and micro, across the board. This may have been placebo, but I did find it to sound slightly more dynamic sounding than the BL, and perhaps that has something to do with the implementation of the new S Balanced circuitry. I am fully willing to admit that may just be in my mind however, as the differences were not huge. From sensitive IEMs to my Susvara and Abyss, the Sig fared well as a transportable option. Being able to run such a wide variety of headphones from such a small, easy to use package is tremendously attractive. The XBASS, and 3D implementations again reminded me of the BL, but the 3D feature did seem to be a bit more cohesive and well tuned sounding. As was my experience with the BL, these are not for everyone, and although I do find that I use the XBASS quite a lot, the 3D feature does see less use. A bit of fun with some types of music however, to be sure.

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iDSD Signature
All in all, the Sig is a slight refinement both in terms of layout/features and sound quality over the previous BL model.

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No more buttons on the bottom.
Now, on to the Diablo. The Diablo is an all new approach to the transportable iDSD form factor. It is a stripped down, fully balanced, more powerful, “track version” vs the “road car” that is the Signature. The Diablo has no XBass or 3D Feature, it has no IEMatch feature. You do get the same low, medium, and high gain modes that you see on the Sig, but that is about it in terms of similarities.

The Diablo comes out the box with a few great accessories. It has a nice tote bag, a 5v iPOWER adapter, and an iPURIFIER3. The iPURIFIER3 is one of iFi’s little USB noise cleaners, and it works well. At the MSRP of the Diablo, $899USD, this is a welcome addition. It also comes with a 4.4mm to dual 3pin XLR cable, which can be use with the 4.4mm output on the rear of the device, to use the Diablo as a DAC only, into whichever amplifier you choose.

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The iPURIFIER 3
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Same Size, different sound.
So, it has less features, but costs over $200USD more than the Sig, you may be asking? Yes. That is it exactly. iFi was clear that the Diablo is meant to be a stripped down, all out performance piece of gear. The best they can currently manage in the small transportable iDSD form factor. By ridding it of the small features the Sig contains, they were able to add on more ultimate performance. Listening to the Diablo, I think they managed.

The Diablo sound more similar to the Neo iDSD which I reviewed, than the BL. Less warm, more detailed, more dynamic. All across the board, it takes the base performance of the Sig and improves it. It is a much more neutral sounding device, and worked well with all three of my main headphones (Susvara, AB1266TC, and Verite.) Due to the fully balanced circuitry vs. The S Balanced of the Sig, the Diablo is able to manage 5000mw into 16ohms peak power, 900mw more than the Sig. This is helpful when you are working with the AB1266TC and especially the Hifiman Susvara (or HE6.) There is no question in my mind, that if you have a particularly hard to drive pair of headphones, and want a transportable option to drive them, the iDSD Diablo is the current standard to beat. There are other options, but none of them present the power, feature set, sound quality, and ease of use that the Diablo does.

This leaves me with a dilemma however. The Diablo is the better sounding of the two devices, yes. Absolutely, there is no question about that in my mind. BUT……if you are driving IEMs primarily, the IEmatch and feature set of the Sig makes it a much more convincing argument to me. If you are driving hard to drive headphones primarily, then I would suggest taking a look at proper desktop size devices, which at the MSRP of the Diablo can be found in forms which will drive those hard to drive headphones in a much more convincing manner.

img_1704.jpg
Diablo Rear
idsdsignature_white_rear.jpg
Signature Rear
So. Who is the iDSD Diablo for then? I think if you are a headphone user, don’t really use IEMs at all, and could care less about the XBass and 3D features, then the Diablo is worth looking at. Apart from that however, I have to recommend the iDSD Signature. It is a more complete package, and cheaper to boot. Most people who are looking for a transportable option, will want it for a wide array of uses. Not just to drive one or two pairs of headphones in particular, whilst at home. Thus, the Diablos use case is much more limited. It does provide the sound quality that is better, there is no doubt about that. It outperforms the Signature in every area of “sound quality”, in my opinion.

The Signature is a welcome refinement of the already great piece of equipment that iDSD Black Label was. It has taken everything, made it more streamlined, and added slight sonic refinements whilst doing it. The Diablo is an interesting top of the line transportable piece of equipment, that if it fits your use case, is unbeaten in my opinion currently. I do however recommend that you really think about the headphones, and IEMs you own, think about how you will use the iDSD of your choice, and try to purchase the one which better fits how you will use it. For me, if I had to choose, I would choose the iDSD Signature. This is due to the fact that I would mostly use my headphones with full on desktop gear, and any transportable option I own, would also be used with IEMs. Thus, the Signature much better fits my needs and uses. However, make no mistake about it, if I wanted a transportable option for my Susvara or Abyss, the Diablo would be the option I would choose, not only against the Signature, but against anything else on the market.
rohanjd
rohanjd
Excellent review! Thank you. Just bought the Diablo yesterday and I am blown away. Anything I've thrown at it sounds so much better. Amazing product indeed!
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drroman66
How would you say it compares with desktop headphone amplifiers, above or below that price range?
ufospls2
ufospls2
Depends. Doesn't compete with some of the higher priced amp only models.

Competes with some of its similarly priced desktop combo unit competition.

Is a no brainer if you need a transportable form factor.

Slater91

100+ Head-Fier
Diabolically good
Pros: Sturdy built with supercar-like design

Possibly the most powerful portable device: 5 W output at 32 Ω!

Balanced output through 4.4 mm jack

Incredible amount of accessories
Cons: Requires separate USB-C cable for charging

Loses all the extra features of predecessors

Charge indicator is impractical

Should have included an IEMatch feature
iFi iDSD Diablo review.JPG


When I was a child, back in the glorious Nineties, I remember I had a model car of what was among the fastest cars back then: the Lamborghini Diablo. It was fantastic and its design and colour really gave the impression of speed and power. Being around 3 years old, I obviously destroyed it and I still regret that. Now, I don't know if the Italian supercar is the inspiration behind the iFi iDSD Diablo, but surely the impression of unrestrained power it gives is the same as the car - and for all the good reasons.

This review was originally posted on Soundphile Review.

Disclaimer: thank you to iFi for sending out this unit on loan. The iDSD Diablo is a hell of a lot expensive (yes, I'm going to make jokes for the whole review), retailing at £999. Additional info on the official website.

Accessories & Packaging​

iFi iDSD Diablo review 2.JPG


The iFi iDSD Diablo comes in a very different package from that of the other micro iDSD devices: it's much larger and more akin to the Neo iDSD. That's because the amount of accessories has increased exponentially and includes:

  • an iTraveller carrying case
  • an iPurifier3 (which is, unfortunately, limited to just the first batch)
  • a 3.5 mm to 6.3 mm jack adapter
  • a USB-A male to USB-A female cable
  • a USB-B male to USB-B female cable (useful if you want to use the iPurifier)
  • a short USB-A male to USB-C male (to charge the
  • a short USB-C male to USB-A male (basically an OTG cable)
  • an optical to mini-optical adapter
  • an RCA to RCA cable
  • a 4.4 mm to double XLR cable
  • an iPower power adapter
  • a barrel connector to USB-C connector (to use the iPower)
The list is quite long and shows the sheer quantity of stuff iFi has put into this box. It's quite a complete set and I can't think of anything I would add to it.

Design & Build​

iFi iDSD Diablo review 3.JPG


Again, I don't know where iFi drew inspiration from, but the Diablo reminds me of a track by Rodrigo y Gabriela, Diablo Rojo. I know, that's quite an original association, isn't it? I totally don't know where I got that from.

It might be this, it might be Italian cars, it might be something else entirely - but as any fan of Warhammer 40000 knows, just the fact that the iDSD Diablo is red makes it faster, which is obviously great. On a less humorous note, the Diablo is obviously very noticeable in that it uses a very eye-catching colour for its chassis, with a black volume knob on the front. It's certainly unique in an industry dominated by serious, often sombre colours. At first I thought that, contrary to the other micro iDSD devices which use metal for their chassis, the Diablo used plastic. That's actually not the case: the iDSD Diablo's chassis is in fact made of metal just like all of its ancestors. The paint finish, though, is remarkably similar in feel to plastic (and a few hot days here in Scotland meant that it was hot enough for the metal not to feel too cold, tricking me into thinking it was plastic).

iFi iDSD Diablo review 4.JPG


The front hosts the aforementioned volume knob, a status LED which indicates the currently-played format (e.g. CD quality, MQA, hi-res, etc), a "turbo mode" switch (a gain switch, basically), a 4.4 mm port and a 6.3 mm port. The back, on the other side (sorry, I had to do this), hosts a full-size male USB-A connector, a female USB-C connector, a 4.4 mm port and a 3.5 mm port for optical SPDIF input. It's a rather complete set of features, but sadly there is no unbalanced line out, which can be a problem if you plan to use the Diablo as a DAC for an unbalanced amplifier.

iFi iDSD Diablo review 5.JPG


As with practically every single device by iFi I've ever tried, the iDSD Diablo, too, is built quite well and leaves no room for criticism regarding this area. If anything, some things have improved: the bottom of the device has in fact four rubber feet embedded in it.

The volume knob has a very good weight to it, so it is relatively hard to turn. While this might seem like a flaw, it is in fact a feature as it allows for very precise adjustments. It has a dead zone which goes from its starting position around 7 to around 10 - so in that area you can expect to have large volume imbalances between channels. This, together with other things, contributes to making the iDSD Diablo difficult to use with low-impedance, sensitive headphones and earphones.

Features & Specs​

iFi iDSD Diablo review 6.JPG


The Diablo is not a replacement for the other devices in the micro iDSD line-up: in fact it offers quite fewer options in terms of output power, filters and so on, only allowing you to select gain (you can choose between Eco, Normal and Turbo). This is in stark contrast to the micro iDSD Black Label, which offered almost any option under the Sun. It's as if iFi decided to take its previous offerings and extract their essence: lots of power and little compromise in terms of how the audio signal is treated. That's a philosophical approach that leads to some compromises, though, so this needs to be thought of carefully.

Unfortunately the volume of the line output is fixed and can't be controlled using the knob.

iFi micro iDSD Diablo

InputUSB (up to 32 bit / 768 kHz PCM/DXDx2, up to DSD512, MQA)
Bluetooth (up to 24 bit / 96 kHz)
Suitable headphones impedance32 - 600 Ω (at least)
Output impedanceN/A
Maximum output powerSingle-ended:
  • 2,417 mW (32 Ω)
  • 153 mW (600 Ω)
Balanced:
  • 4,980 mW (32 Ω)
  • 611 mW (600 Ω)
Frequency response10 - 80,000 Hz
THD+N (@1 kHz)< 0.002% (balanced)
< 0.001% (single-ended)
SNR> 120 dB (balanced)
> 114 dB (single-ended)
CrosstalkN/A


As is tradition for iFi, the iDSD Diablo uses a Burr-Brown DAC. The company mentions "[t]he Burr-Brown True Native® chipset" in its material, so I'm taking a guess and say there is a single DAC chip in this device, leading to it not being a "true" balanced design.

iFi iDSD Diablo review 7.JPG


On the other hand, the amount of power the iDSD Diablo gives you is astonishing and well into the territory of large desktop amplifiers. At an output power that's just short of 5 W at 32 Ω (theoretically double the output of the micro iDSD Black Label!), this device can drive anything under the Sun save for some earspeakers (e.g. Raal Requisite SR1, AKG K10000, etc). Speaking of output power, the lack of the IEMatch switch is felt when you try to use the Diablo to drive IEMs: it's just too powerful for them, so it ends up being just too loud without using an actual IEMatch or adjusting the volume via software on the source device.

Now, there's also something to be said about the steps of the gain selector. The difference between them is quite large, so going from one to the next means that you get a very large jump in volume, more so than on other amplifiers. This, coupled with the lack of an integrated IEMatch feature, means that it might be hard to use the iDSD Diablo with lower-impedance headphones.

Battery Life​

The iFi iDSD Diablo offers a whole day of activity, which clocks in at around 10 hours using relatively easy to drive headphones and the "eco" mode. The figures will probably be lower when using more demanding headphones, but the result is still quite good.

A major annoyance, though, is the lack of any indication that the battery is running out of charge and the necessity to use a second cable to power the device. "Traditional" desktop use is not quite as convenient as with previous micro iDSD devices, as you have to connect the Diablo to a charger for desktop usage - with all the inconvenience that this entails, of course. I would consider this a desktop device that you can optionally use on a battery, a bit like the Head 'n' HiFi Objective2 amplifier.

One thing about the battery is that it is always used. Even if you plug in the device to the mains outlet, that current will be used to charge the battery which is then going to power your headphones. There is just no way to use the power adapter directly to power your headphones. While this can have a good effect on audio (battery power is, by definition, clean and devoid of noise), on the other hand this might be an issue down the road, as after a few years of use I imagine the battery is going to give up and to be in need of replacement.

This also means that the iPower provided with the device is actually useless: it should theoretically offer less noise and therefore improve the performance of a connected device, but in practice this supposed positive effect is cancelled by the fact that the power to drive your headphones comes from the battery anyway.

Sound​

I tested the iFi iDSD Diablo using my notebook computer, an HP EliteBook 745 G5, and FLAC files (most ripped from CDs).

Despite removing the IEMatch feature, the iDSD Diablo is absolutely dead silent, even when using it with sensitive earphones.

Just like its predecessors, the iDSD Diablo doesn't really have a sound signature of its own that I can discern. In fact it is completely neutral to my ears, as I can hear no differences when comparing it to other DACs and amplifiers. As it offers an insane amount of power, it can drive anything I throw at it without breaking a sweat and with very good speed, too. Maybe (let's put some stress on it: maybe) there is a tad more micro-detail here compared to other devices such as, say, the nano iDSD Black Label - possibly thanks to the pitch black background.

One thing that I miss here is the various options that were there in previous models, such as XBass and 3D+, but the choice of iFi of focusing on pure performance has the side effect of removing these options.

Final Thoughts​

While thinking about what mark I should award the iFi iDSD Diablo, I thought: "you lose some, you win some". And that's exactly what has happened with the Diablo: it got some improvements over its predecessors, but at the same time it gave up some features. It's rare to see a company so hell-bent into creating a portable amplifier so powerful it beats most desktop counterparts, but here we are. And with this also come some compromises.

The iDSD Diablo has a lot of things I really like, from the incredibly powerful output to the balanced port, from the vast amount of accessories to the optical input. It also misses a few things I would have liked to see, such as an IEMatch feature to better drive sensitive earphones. All in all, though, the Diablo is incredibly competent and a great option if you want to experience the sound of very-hard-to-drive headphones with a small DAC/amp instead of large desktop devices. It's just fiendishly good at that.
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drroman66
Appreciate it. Looking for something for my nightstand with a bit more oomph and refinement than my Fiio M15. I would most likely use line out on my player. Do you think this would fit the bill?
Slater91
Slater91
@drroman66 This would certainly have much more oomph than your M15. Whether it fits the bill for you depends on what headphones you would like to drive with it.
senseitedj
senseitedj
yeah, I've thrown everything with this device. Can power my sensitive LCD-4z, and even the power-hungry Beyer t1 (600 ohm), HEDDphones, and Abyss no problem. Does IEMs respectably too, no hissing detected.

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