Hiby R8II (Pre-Order)

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Hiby's proprietary DARWIN DSP and digital filter design has paid off in R8II – Head-Fi's groundbreaking, first totally original, discrete pulse-width modulated (PWM) music player.

With DARWIN having gained prominence in HiBy's R2R RS6 and RS8 players as software specially written for hardware, the oversampling, noise-shaped PWM R8II is an even further step as a digital creation.

This PWM prodigy eschews the impractical dependance on parts precision necessary in analog circuits and filters to perform. Rather, R8II's shifts the hard work into the digital realm. HiBy loaded code aboard R8II's FPGA to run its PWM DAC with a frequency and time domain accuracy only possible with high-speed DSP. 

All these gains in decoding digital to analog translate to a newfound realism and accuracy in playing music back via the Android 12 R8II, which comes with HiBy's now-standard discrete Class A 4.4mm headphone amplifier capable of driving a new generation of low-impedance flagship earphones.

  • Starlight Silver
  • Bordeaux Red
  • Prussian Blue


Instead of being a mere drive towards cost-effectiveness, the PWM R8II – dubbed DARWIN Multi-Phase Array (MPA) – unlocks a new era of sustainable portable performance in DAPs. 

Its pulse-width modulation decoding of digital via individual capacitors and resistors is already a one-up on the standard delta-sigma modulation typically found in DAC chips.

HiBy's DARWIN MPA addresses the problems of conventional delta-sigma's inconsistent rise and fall edges at the frequency level, with adjustments made to facilitate more accurate, predictable switching on and off between 1s and 0s. This approach results in a reduction of errors by avoiding intersymbol interference.

Notably, non-linearities arising from rise and fall mismatches do not manifest as total harmonic distortion. R8II's PWM decoding does not produce harmonic errors that vary with digital output levels.

The brains of R8II are contained within its FPGA running a second generation of DARWIN digital filters. HiBy has cracked the formula for simultaneous time and frequency domain performance via its proprietary code.

Certainly, digital can only claim to be high-performance if it oversamples heavily past the problems of Nyquist. And R8II is such a fruition of this ideal being developed entirely in-house at HiBy. DARWIN digital filters oversample incoming PCM data by 128x. These formats are put through a discrete MPA DAC running at an incredible speed of 6.144 Mhz.

Shifting the Nyquist frequency exponentially beyond the range of human hearing enables the associated digital filter to function with a shallow profile. This allows for the effective blocking of aliased digital frequencies, while concurrently enhancing time-domain performance by minimising impulse ringing – a contrast to what a standard steep digital filter might induce.

Importantly, this approach dramatically relaxes demands on the parts precision of any subsequent analog low-pass filter following R8II's DARWIN MPA DAC. Not that its discrete current-to-voltage I/V converter – made of individual transistors – has a problem dealing with any remaining distortion presenting itself as a DC offset that is easy to filter out.

The dynamic element-matched, multi-bit output of R8II's DAC is precious. Indeed, HiBy's discrete I/V stage has the high slew rates and instant step response necessary to keep up with the more linear phase of DARWIN MPA's shallow digital filters.

Whatever entered R8II's DAC as digital comes out exactly the same in analog due to this I/V's low open-loop gain – with lower negative feedback necessary leading to its high speed, plus high slew rates and unity gain stability. 

There's a reason R8II portrays elements within the soundstage with such solidity, despite aural image tangibility not normally being the strong suit of 2-7 bit delta-sigma or PWM designs.

Indeed, the elements within the soundstage this HiBy generates are convincingly rendered because its small analog signal post-conversion is of the highest quality, and inherently stable without going into oscillation caused by too much I/V gain product.

HiBy's decode goes through a four-channel analog volume control before reaching the Class A discrete output stage, preserving your music's true dynamic range resolution.

R8II's power supply rails see operating voltages for its power section sit at a nominal 6 volts that Turbo Mode boosts to 7.5, assuring the open-loop linearity of discrete transistors. HiBy's discrete amplifier can be operated in Class AB or an optimal Class A, for sonic tweaking with your favourite earphones and headphones.

Differentiating itself from even other flagships that cling to op-amp layouts seeking THX-certification but with inordinate amounts of gain and feedforward/feedback, R8II's linearity remains excellent already in the open-loop, owing to its high operating voltages and bias.

Those ensure individual transistors are working in optimum condition. Distortion and noise are kept low, without resorting to the excessive use of negative feedback.

HiBy designed a true-balanced differential amplifier to further improve R8II's linearity, and you can count on common-mode rejection at its best whenever you plug in via 4.4mm preserving its resolution.

At the tip of R8II's power stage spear, 16 transistors ensure excellent current-handling for good reason, to reap the full benefit of HiBy's separately regulated power supplies for analog and digital sections. 

The former is particularly massive and incorporates inductors that store huge energy in a magnetic field before releasing on demand to HiBy's Class A amplifier. 

You'll want to exploit all of R8II's technical feats by getting as much of your music aboard. So HiBy built in the futuristic Snapdragon 665 SOC and 8GB of RAM to run Android 12 and Google Play Store perfectly.

A 12,000mAh battery supplies up to 20 hours of use. Stream Hi-Res Lossless Tidal and Apple Music at full bit and sample rates with HiBy's Direct Transport Audio OS that bypasses detrimental Android sample-rate conversion.

And an alcantara-covered backplate and stainless steel chassis means you'll always listen to R8II in style. It's style that absolutely comes with substance, containing a HiBy heirloom.

A heirloom that cumulates as a symbol for how far they've come turning their code into truly groundbreaking products and musical nirvana.