iDSD Diablo-X from iFi audio

eXperience innovation

The very first DAC/amp in the world to drive xMEMS technology


The Diablo-X is the first DAC/amp on the market to support the revolutionary xMEMS solid state monolithic speaker technology. 

This unique technology features:

  • Ultra-fast mechanical response (~15µsec; 150x faster than a typical dynamic driver)
  • Flat 2° phase response for more accurate sound reproduction
  • +/- 1° phase matching (part-to-part) for more accurate spatial sound
  • Silicon speaker diaphragm (95x more stiff/rigid than plastic) for reduce speaker break-up (less muddy mids/highs)

Brian Lucey, 8-time Grammy Winning Mastery Engineer, calls it “truly disruptive’ with “phase performance unlike no other speaker technology”.  Discover why in 3 minutes.

This level of performance requires a higher voltage solution to drive it, so iFi have partnered with XMEMs to produce the Diablo-X – a first to drive a first!

xMEMS eXplained

The xMEMS micro speaker technology uses the piezoelectric effect to create a paper-thin solid-state speaker. These micro-speakers offer great potential to push the boundaries of IEM and headphone performance.

As xMEMS themselves say, “The inverse piezoelectric effect is created by applying electrical voltage to make the piezoMEMS contract or expand, converting electrical energy to mechanical energy. This energy excites an integrated silicon membrane to move air and generate acoustic sound waves…. xMEMS’ piezoMEMs actuators offer an increased range of movement enabling rich, loud audio”.

Diagram taken from

iDSD Diablo-X from iFi audio

Still devilishly delightful…

The Diablo-X can still also be used with your favourite IEMs/headphones and, just like the original, uses two Burr-Brown DAC chips and the 16-core XMOS chip to process the data received via the USB and S/PDIF digital inputs. This means the Diablo-X can handle up to PCM 768, DSD 512, 2xDXD. Both PCM and DSD remain ‘bit-perfect’. It provides full MQA decoding.

Balanced, differential analogue circuit design reduces noise and cross-talk within the signal path by fully separating the left and right channels. The Diablo-X includes our PureWave tech – refinements to our balanced, symmetrical dual-mono topologies with short, direct signal paths.

Negative feedback is used in amplifier circuits to compare the output signal with the input signal and correct errors. BUT there are drawbacks. iFi turns the negatives into positives with OptimaLoop. Read more below.

iDSD Diablo-X from iFi audio

…and diabolically driven.

Able to drive all manner of headphones with ease, including those incorporating the new XMEMs tech, the Diablo-X sports fully balanced 4.4mm outputs with a maximum 4,100mW of power.

Three modes are used to adjust power and gain.

  • xMEMS – use with compatible IEMs/headphones
  • Turbo – ramps up the level of drive for current-hungry headphones
  • Normal – for most over or on ear headphones
iDSD Diablo-X from iFi audio

Perfect pairings

While we were working on the Diablo-X, two companies were pushing the boundaries to deliver XMEMs compatible earphones.

Singularity have created the ONI. This sleek, minimalist looking IEM contains two xMEMS drivers to deliver superior sound.

And Soranik are firing things up by combining both xMEMS and USOUND technologies in their new MEMS-2! Available within 21 days.

iDSD Diablo-X from iFi audio

Unadulterated performance

The Diablo-X focuses on pure unadulterated performance, meaning that much attention has been applied to the power supply circuitry.

Battery power provides ultra-clean and stable DC current avoiding the issues of mains electricity – dips, spikes and noise-inducing RFI/EMI pollution. BUT there are sonic downsides resulting from low output voltage and inconsistent output impedance as batteries discharge.

In order to make less efficient headphones, like planar magnetics, sing, the voltage needs to be stepped up from 3.7V to +/- 15V.  We use 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.

Unrivalled components

High-bandwidth power supply circuitry is dedicated to each critical part of the Diablo-X’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 multi-stage filtering, and the microprocessor control circuitry (often a local source of digital noise) has separate regulation, too.

Crucial components for maxed out performance, more below.

iDSD Diablo-X from iFi audio

The devil is in the detail

Whether you are using your favourite IEMs/headphones or a pair of xMEMS compatible IEMs, the Diablo-X connections have you covered.

At the front of the unit, alongside a standard 6.3mm single-ended headphone socket, resides a 4.4mm Balanced output for headphones offering balanced connection.

At the back are two digital audio inputs: USB-A and a S/PDIF socket that accepts both electrical and optical signals, the former via a 3.5mm connector and the latter via a supplied adapter.

The USB-A input features a ‘male’ connector, rather than a typical ‘female’ port for greater mechanical integrity.  A separate USB-C charging port is also provided, along with a 4.4mm Balanced output to connect to an external amp.

The piezoelectric effect

The piezoelectric effect is a phenomenon in which certain materials generate an electric charge in response to mechanical stress or pressure applied to them. The word “piezoelectric” is derived from the Greek word “piezein,” which means to squeeze or press.

When a piezoelectric material, such as certain crystals or ceramics, is subjected to mechanical force or stress, the arrangement of its atoms or molecules is altered, leading to the generation of an electric charge. This effect is reversible, meaning that if an electric field is applied to the material, it can cause a deformation or change in shape.

The piezoelectric effect arises from the asymmetry of the crystal structure of the material. Inside the crystal lattice, positive and negative charges are distributed asymmetrically, leading to a dipole moment. When stress is applied, the crystal structure deforms, causing a shift in the center of charge distribution and resulting in the generation of an electric field.

The piezoelectric effect has proven to be a valuable property in engineering and technology, enabling precise control and measurement in many applications.



The XMOS 16-Core chip processes the audio data received via the USB* digital input.

This low-latency XMOS microcontroller has greatly enhanced processing power. Compared to the current generation of eight-core chips, this 16-core IC delivers double the clock speed (2000MIPS) and four times the memory (512KB), as well as the latest SuperSpeed USB standard.

iFi’s in-house digital development team has programmed the XMOS firmware to optimise sound quality and ensure a perfect partnership with the Burr-Brown DAC.

(* Also on S/PDIF on the Diablo-X)

Extensive jitter-eradication technologies are applied to the digital stage, including our GMT (Global Master Timing) femto-precision clock and intelligent memory buffer. This represents a total ‘out-of-the-box’ systematic digital solution that solves jitter once and for all.

The Burr-Brown True Native® chipset means file formats remain unchanged or ‘bit-perfect’. This means you are listening to music as the artist intended in the format in which it was recorded.

At iFi we use Burr Brown extensively in our products having selected it for its natural-sounding ‘musicality’ and True Native architecture. Our experience with this IC means we know how to make the most of it.

An important aspect of the circuit design is its direct-coupled nature (no coupling capacitor is present), achieved without a conventionally applied DC servo.

DirectDrive® equals a direct signal path which means less signal degradation. This direct signal path is unequalled in audio and is the reason why the sound is so ‘true’.

MQA (Master Quality Authenticated) is supported through the USB with full decoding of MQA files up to 384kHz thanks to the processing power of the new 16-core XMOS chip.

Check out how to set up your MQA decoder via Tidal, Roon and Audirvana here.

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. It is available through for Tidal Masters, Audirvana and Roon.

‘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 also highlight different problems at the same time as solving others – corruption of the error signal, phase shifts, group delay and so on can all have a negative impact on sound quality.

We recognised that different parts of a circuit benefit from specifically optimised feedback loops and have developed a negative feedback system that is much more accurate than the usual approach. This incorporates multiple feedback paths instead of a global loop, each path optimised for a particular function and working synergistically with the others to deliver optimal overall performance.

As with many other iFi audio products, we’ve incorporated a custom OV Series operational-amplifier. This top-notch component contributes to the extremely low noise, low distortion (0.0001%) and wide bandwidth.

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.

PureWave is a new, balanced, symmetrical dual-mono topology with short, direct signal paths. The name refers to the sonic purity it achieves thanks to exceptional linearity and infinitesimally low levels of noise and distortion.

Switching between settings has been engineered to ensure sonic transparency with advanced trench technology MOSFET is used as a muting switch.

This FET-based switching is handled by a micro-controller, which only ‘wakes up’ when the user changes a setting, thus eradicating any sonically deleterious interference.

TDK C0G (Class 1 ceramic) capacitors offer high stability and low losses for resonant circuit applications.

Getting ever closer to the theoretical ideal of pure, frequency-constant capacitance, these capacitors reduce capacitor-induced distortion to vanishingly low levels.

They are pricey but are a perfect addition to our products.

Vishay MELF resistors – complex, costly but superior.

These metal electrode leadless face resistors have excellent accuracy, stability, reliability, and pulse load capability. They provide optimal power rating and pulse load capability. They show some of the lowest noise and distortion of any resistor available in the market, period.

Panasonic OS-CON caps totaling 5,410uF give very-low Equivalent Series Resistance (ESR), excellent noise reduction capability and frequency response characteristics. In addition, OS-CONs have a long-life span and its ESR changes little even at low temperatures since the electrolyte is solid.

They are not often found in products costing <US$1000.

Texas Instruments low-noise ICs offer great unity-gain bandwidth, very low noise and distortion, high output drive capability, Common-mode and Power Supply Rejection Ratios of over 100 dB, wide maximum-output-swing bandwidths and high slew rates.

muRata control-type, low-ESR high-Q multi-layer capacitors. The ‘ESR control’ aspect of the Murata is something special. Their noise suppression abilities are impressive.

iDSD Diablo-X

Read Reviews




Digital InputsUSB 3.0 type 'A' (USB2.0 compatible)
S-PDIF (3.5mm coaxial/optical)
Formats supportedDSD512/22.6MHz
PCM 768kHz
MQA Full Decoder
DACBit-Perfect DSD & DXD DAC by Burr Brown
Frequency Response10Hz-80kHz(-3dB)
Dynamic rangeBalanced
THD + NBalanced
Headphone Max OutputBalanced

>28Vpp (@ xMEMS)
>19.2V/611 mW (@ 600 Ω)
>12.6V/4,980 mW (@ 32 Ω)
>9.6V/153 mW (@ 600 Ω)
>8.8V/2,417 mW (@ 32 Ω)
Fixed Audio OutputBalanced 4.4mm
Power consumptionXMEMS
BatteryLithium-polymer 4800mAh approx.
Power SystemCharging via USB-C
BC V1.2 compliant up to 1000mA charging current
Dimensions166 × 72 × 25 mm
(6.5"x 2.8" × 1.0")
Net weight330g
(0.73 Ibs)
Limited Warranty12 months

“Exciting, New Technology!”

“The Diablo-X is the first device on the market that has a special circuitry built for xMEM IEMs.”
Discover more by reading the full review.

Mate Szeverenyi

(Click name to read original review)

“Want improved sound when listening to tunes, podcasts, or watching TV shows, movies, and sports from your phone?”

“…You can achieve that with a portable DAC like the iFi audio Diablo X, which was introduced earlier this year.”

Wifi Hifi

(Click name to read original review)