Review: HiBy R6 Pro II

Specs and features

R6 Pro II continues the theme of using desktop-grade parts in portable devices. Except that theme is usually reserved for much more expensive players, and almost exclusively to flagships. 

Not only has HiBy specked the new Pro with dual AK4499EX DACs and a single AK4191EQ digital controller – the new flagship-grade, full-power desktop DAC components from AKM – they also enabled all eight DAC cores in a dual-mono, octa-DAC configuration. HiBy calls this architecture ‘All In’, and if I’m not mistaken, it’s a first for any DAP using these DACs. I wouldn’t be surprised if it’s one of the first such implementations on most dedicated full-size desktop DACs too. 

This DAC horsepower allows HiBy to continue boasting the highest decoding spec of any DAP on the market: DSD1024 (native) and 32-bit/1536kHz PCM. Heck there’s probably only a handful of desktop DACs that can match these specs, and while this level of music file fidelity is mostly hypothetical, it does allow for considerable headroom should hi-res music encoding technology continue to advance. 

All this decoding power would be academic if it lacked a sufficiently robust amplification stage, and that’s where things get a little murky with the new Pro. While you’re still getting HiBy’s new switchable Class A/AB amp circuit, including two desktop-class OPA1652 and eight NXP bipolar transistors, the power output has been cut back to barebones: 125mW single-ended and 383mW balanced (with a 32Ω load). That’s only slightly more powerful than Sony’s notoriously ‘underpowered’ S-Master players (including the WM series).

I’m in two minds about this. On the one hand, and as you’ll see in the sound impressions tests below, the combination of DAC horsepower with true Class A amplification is more than enough to drive even power-hungry IEMs sufficiently, and most IEMs optimally. 

On the other hand, it does make R6 Pro II less versatile with full size headphones, and while I’d argue that even flagship DAPs with three or more times the power are still not ideal for most large headphones, it does tend to make R6 Pro II an IEM-only DAP, at least for those who want to maximise the sound quality of their drivers. 

To be clear: R6 Pro II will drive any and all IEMs just fine. It’ll easily reach deafening volume levels even in low gain, with more than enough headroom to spare for harder-driven IEMs in with two additional gain levels. 

But, I would not recommend using it with anything other than very sensitive full-size headphones, and definitely not with high-ohm, low-sensitivity dynamic driver or planar headphones. You’re just wasting their potential otherwise, even if you think they sound okay.  

Switching between Class A and AB amplifier modes has a subtle effect on dynamics and stage size, and also helps to smooth out some vocal artefacts in poorer recordings. The biggest impact of switching from A to AB, though, is battery life. 

With a mid-sized 5000mAh battery, desktop DACs (clocked at full tilt) and Class A amplification, the battery will drain in as little as four hours, depending on how long you keep the screen on, if you’re using the balanced output, and if you’re also using WiFi to stream. 

Thankfully that’s a worse-case scenario. ‘Normal’ use – balanced, Class AB, and a mix of streaming and local files, should yield a more respectable six to eight hours’ use, and playing back mainly local files with little to no screen time will get you just over 10 hours per charge with the same settings. 

So yeah, just like flooring your Ferrari will burn significantly more gas, flooring the hardware in the new Pro is so worth it – battery life be damned!

Full specs:

  • Dual AK4499EX DAC (all 8 cores active) + AK4191EQ
  • Qualcomm SnapDragon 665 / 4GB RAM
  • Class A/AB amplification (2x OPA1652 op-amps + 8x NXP bipolar transistors)
  • 64GB storage/4GB RAM
  • 5.9” 1080×2160 (2K) IPS touchscreen display
  • Lightweight (248g) all-aluminium and glass chassis
  • 5,000 mAh Battery with PD 2.0 and QC 3.0 fast charging
  • Bluetooth 5.0 + WiFi 2.4GHz/5GHz
  • Native Android 12 OS with DTA support
  • 16X hardware MQA decoding support
  • 4.4mm balanced + 3.5mm single-ended true line-out + headphone ports
  • USB-C 3.1 I/O with external DAC and OTG storage support 

Wires and wireless 

Like its modern siblings, R6 Pro II features all the connectivity options you could possibly want in a portable music player. This includes a dedicated wired DAC mode, which lets you use the DAP as a portable DAC for laptops, phones and tablets, mostly without additional drivers. Sadly you won’t get the full decoding specs in DAC mode (like DSD1024), but they’ll still be respectable and more than you’ll likely use anyway.

R6 Pro II also includes full 2.4GHz and 5GHz WiFi support, letting you make use of more advanced functionality like DLNA/UPnP streaming and wireless file transfer at full gigabit speeds. Testing R6 Pro II alongside my smartphone showed little to no difference in WiFi transfer speeds, a real plus considering many DAPs have crippled WiFi support with less than optimal range and speed.

Bi-directional Bluetooth 5.0 is also present, with the full array of codecs, including ‘hi-res’ UWC and LDAC, AptX HD for Android users, and basic AAC/SBC for the iPhone brigade. You can use R6 Pro II as a wireless DAC in Bluetooth Sink mode, or connect any number of headsets and TWS IEMs. Bluetooth range was more than satisfactory in practice, holding a strong connection to my Sony WF-1000XM4 TWS IEMs over 20 metres and between two sets of concrete walls. 

Overall the hardware side of the new Pro is not just impressive, but bar-raising for a DAP at this price point. If sound quality comes anywhere close to matching the potential of the hardware, this DAP will likely set a new price-performance marker for portable sources. 

Continue to software, UX and performance…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


2 Responses

  1. Fabulous review! With so much detail and thought.

    Any view on how these compare to the shanling m6 ultra? And would pairing the R6P2 with an amp like the Topping NX7, be able to drive full sized headphones like say Sennheiser HD650s?

    1. Thank you. I have not used the Shanling so can’t say, but yes, connecting the R6 Pro II via line-out to an external amp will easily power full-size headphones.

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