Review: Hidizs XO – Portable Audio Gamification

The XO brings decorative LEDs to the dongle market.
The XO brings decorative LEDs to the dongle market.

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The flashy XO bedazzles a tried-and-true approach to the portable DAC/amp dongle.

Thank you to Emma and Hidizs for providing the XO for review purposes.

If you want to create another product for an already crowded marketplace, how do you differentiate it from the rest? This a question that manufacturers face more and more each day.

Fierce competition drives companies to be creative and to offer more features for less money. Sometimes these features are ground-breaking improvements that push innovation and benefit everyone. Sometimes they serve to differentiate a product by making it more attractive to a specific demographic.

For the last decade or so, LED lighting has defined gamer style and accessories. What makes a headset, fan, keyboard, or computer case even better? Multi-colored lights, of course! One can transform consumer-grade products suitable for mere mortals into elite gamer-specific weapons with the liberal addition of flashing, breathing, or glowing RGB LED goodness.

Bottom Line

At the near USD$100 price point, the Hidizs XO is a decent option for a portable DAC/amp. The ESS SoC architecture works well, and the XO offers little in the way of sonic surprises - good or bad. It’s very well constructed – small, smooth, solid, yet lightweight. The LEDs are a missed opportunity. The O filter button is another miss, with currently only two filter options that make very little audible difference. Playback or volume buttons would be a more useful choice. The LEDs and X-O buttons make the XO stand out amongst its peers, but in every other way, the XO is a typical, if well-made, portable DAC/amp dongle.

What We Like 😍
  • Attractive form factor and design
  • Robust build quality
  • Small size and weight
  • LEDs work well
  • Reasonable price
  • Hi-Res format support, including MQA
  • Single-ended and balanced outputs
  • Uncolored sound
What We Don't Like 🤢
  • LED lights are not synchronized with the sound
  • LEDs drain the source battery
  • Consumers seem to prefer a 4.4mm to 2.5mm balanced output
  • Audio filters are too subtle to distinguish
  • No Lightning cable included
  • No volume control buttons or display
  • Seems less powerful than the specs would suggest

Indeed, some portable audio enthusiasts are gamers, and it seems Hidizs is aiming their newest portable DAC/amp dongle, the XO, firmly at this group. Two major design factors differentiate this otherwise ordinary tiny aluminum brick from the competition.

The first is multicolored LEDs (of course) running the length of both sides. The second is the two prominent buttons on the front surface, an ‘X’ and a glowing ‘O’. The X and O symbols are iconic gaming console controller button labels.

In this case, the X rotates through fourteen (!) different lighting effects while the O selects audio filters.

‘XO’ has distinctly different meanings in western culture. In the military, the XO is the second-in-command executive officer. In letter writing, XO stands for hugs and kisses.

Is the Hidizs XO all flash and no substance, or is it a gaming audiophile’s portable weapon of choice? Hugs and kisses or executive officer? Grab a controller, chug a Red Bull, and join me on the couch to find out if “the cake is a lie.”

The X and O buttons are distinctive.
The X and O buttons are distinctive.

Company Overview

Hidizs (pronounced ‘hid-is’) was founded in 2009 by a group of technicians with HiFi audio research and development experience that aimed “to produce a superior and affordable pocket HiFi audio device.”

In 2010 they started researching the global HiFi audio market, and they officially finalized their team in 2012. The AP100, launched in 2014, was the first music player created by Hidizs. In 2017, they funded the AP200 DAP through Kickstarter.

2018 saw the release of the original AP80 DAP, and in 2019 the Hidizs team branched out and produced the Mermaid MS4 IEMs.

Now the Hidizs company offers several different DAPs, IEMs, Bluetooth modules, amplifiers, and accessories.

Technical Specifications

  • Form: Portable DAC/Amp
  • Chipset: ESS Sabre ES9219C
  • Frequency Response (Hz): 20 Hz – 40 kHz
  • THD+N: 0.0015% 3.5mm, 0.0005% 2.5mm
  • SNR: 118dB 3,5mm, 119dB 2.5mm
  • Crosstalk: 76dB 3.5mm, 118dB 2.5mm
  • Output Power: 78mW @32Ohms 3.5mm, 195mW @32Ohms 2.5mm
  • Removable Cable: Y, USB-c
  • Output Jacks: 3.5mm TRS, 2.5mm balanced TRRS
  • Weight (g): 11
  • Dimensions: 55 x 24.5 x 9.35mm
Hidizs boxes all follow the same basic design.
Hidizs boxes all follow the same basic design.

Packaging

Hidizs products all seem to come in small black boxes with product pictures on the top and tech specs on the bottom. The XO box is no exception, although the box under the cardboard sleeve is made of plastic rather than paper this time. Inside you’ll find the dongle with the accessories underneath.

In the box

  • XO portable DAC/amp
  • USB-c to USB-c OTG cable
  • USB-c to USB-a adapter
  • Warranty card
iPhone users will lament the exclusion of a Lightning cable or adapter.
iPhone users will lament the exclusion of a Lightning cable or adapter.

The plain black USB-c to USB-c OTG cable is nothing extraordinary but works well. The included USB-c to USB-a adapter is appreciated, but iPhone users will note the lack of a USB-c to lightning cable.

The USB-c port is on the bottom.
The USB-c port is on the bottom.

Design

The XO is a lightweight (11g) small aluminum brick available in three colors, silver, black, and rose gold (as tested). It feels smooth, solid, and well-made.

To be honest, a flashing pink dongle is not my first aesthetic choice, but reviewers can’t be choosers.
3.5mm single-ended and 2.5mm balanced jacks.
3.5mm single-ended and 2.5mm balanced jacks.

The bottom end has the USB-c port, while the top contains both 3.5mm single-ended and 2.5mm balanced ports. The headphone outputs are close together, so don’t expect to use both simultaneously.

Consumers seem to gravitate to 4.4mm balanced outputs and cables these days, so including a 2.5mm socket may put some purchasers off.

The X and O buttons are on the front face, while the back has the ESS and MQA logos, “32Bit/384kHZ DSD256”, and “Hidizs XO Single-ended & Balanced MQA Dongle” engraved in white. Custom engravings also show up on this side.

Along both long sides are grills made of tiny ‘H’ shaped holes; this is where the LEDs shine through and give the XO a retro sci-fi look – it makes me think of 1960s Star Trek Enterprise wall grills.

The LEDs shine out of all those tiny little H-shaped cutouts.
The LEDs shine out of all those tiny little H-shaped cutouts.

The 14 preprogrammed LED patterns flash between red, green, blue, purple, cyan, and pink and are changed by repeatedly pressing the X button.

Unfortunately, you must unplug the XO or cycle through all the options to turn the LEDs off.

The big miss here is that there is no connection between the music and the light show. Dancing level indicators adding a visual element to the music are a win. Unrelated flashing lights, on the other hand, are not.

The LEDs don’t add to the listening experience.

A near Christmas release date will bring inevitable comparisons to Christmas lights.
A near Christmas release date will bring inevitable comparisons to Christmas lights.

Around the O button is a multi-color LED ring that indicates the file format currently being decoded. It also changes color between red and blue when selecting the digital filter.

O button LED indicator

ColorFormat
RedPCM 352.8/384 kHz
PinkMQA
YellowPCM 176.4/192 kHz
GreenPCM 44.1/48/88.2/96 kHz
BlueDSD 64/128/256

Internals

The XO features dual ESS Sabre E9219C DAC chips capable of decoding 32-bit/384 kHz PCM, DSD256, and MQA 16X. These are impressive capabilities for a device this small and affordable. Additionally, high-precision independent crystal oscillators are intended to improve the data connection quality.

Signal-to-noise and total harmonic distortion numbers are equally remarkable.

On paper, the power output is relatively high, 78mW @32Ohms single-ended and 195mW @32Ohms balanced. This is sufficient for almost any pair of IEMs and efficient full-sized headphones. Planar-magnetic or inefficient headphones will likely require more power than the XO can provide.

Since the XO has no internal battery and is powered from the source, I wanted to know the impact of all those LEDs on the battery. I broke out my FNRSI FNB48 USB voltage and current detection meter and tried toggling the XO LEDs between modes and on/off.

As expected, the drain fluctuated depending on the LED activity, from about 1.3A (off) to 1.5A (on) – about 15%.

Source battery life is the price you’ll pay for the light show.

Measuring the power draw using a FNRSI FBN48.
Measuring the power draw using an FNRSI FBN48.

Hidizs XO Sound

I tested the Hidizs XO primarily with my iPhone X and a variety of IEMs – including the Thieaudio Monarch, DUNU Kima, and Tangzu Audio Zetian Wu – and headphones – including the Sivga Oriole, Audeze LCD-5, and Koss Porta Pro.

I’m a huge fan of the AP80 PRO-X DAP, which shares the same ESS9219C chipset as the XO. Since this chipset is an SoC (System on a Chip) that incorporates both DAC and amplifier functionality, the end sonic result is similar between these two devices.

Testing out the XO.
Testing out the XO.

That’s not a bad thing. With the XO, you get a competent, tried-and-true design with sufficient power and sonic quality. Manufacturers using this chipset can do little to improve or change the sound, but this provides assurance that you’ll hear what you expect.

Digital filters can subtly alter the output, but in the case of the XO, the two filter options (blue/red) are essentially indistinguishable.

“Switching filtering currently has two effects. The blue light effect is named blue, the same as the red effect. One of the frequency bands is reduced, the high-frequency band is reduced, and the voice and low-frequency sound are slightly enhanced…” – Hidizs in email communication
PCM filter frequency response comparison between the 'blue' (top) and 'red' (bottom) filters on the XO. Graph provided by Hidizs.
PCM filter frequency response comparison between the ‘blue’ (top) and ‘red’ (bottom) filters on the XO. Graph provided by Hidizs.

Technically speaking, the blue is a linear phase fast roll-off filter. The red is a hybrid roll-off filter. In blind listening tests, I can’t reliably tell the difference between them. It seems a bit of a waste to dedicate the filters to one of the two buttons on the device.

Overall, the XO sounds clean, uncolored, and reasonably articulate. It doesn’t significantly alter the music it plays, neither boosting nor reducing frequencies. Think of it as a reliable and accurate portable audio source.

It will likely be a more robust and cleaner-sounding output than most phones with a built-in 3.5mm output. The XO preserves the sonic signature of IEMs or headphones that it can adequately drive and adds no unwanted noise or hiss.

In use, the XO couldn’t be simpler. The O filter button can be ignored, and the X button changes the light show – plug it in and control your music from the source device. The resulting sound is uncolored and transparent.

The sonics aren’t particularly exciting, but the XO is a solid performer for its near USD $100 price point.

The XO and its older brother the S9 Pro.
The XO and its older brother the S9 Pro.

Hidizs S9 Pro Comparison

For a few bucks more, the older but well-respected Hidizs S9 Pro offers a little more output power on paper (100mW SE, 200 mW balanced), higher format decoding (but no MQA), and a more impactful sound.

In use, the S9 seems more dynamic and powerful than the XO – it’s far louder at the same source volume level. The XO sounds smoother and more rounded off than the S9, the latter gives a crisper impression of higher detail portrayal.

To my ears, the S9 Pro is the way to go, and the price difference between the two is fairly negligible these days.

Where to Buy

Are those lights enough to tempt potential purchasers?
Are those lights enough to tempt potential purchasers?

Conclusion

At the near USD$100 price point, the Hidizs XO is a decent option for a portable DAC/amp. The ESS SoC architecture works well, and the XO offers little in the way of sonic surprises – good or bad.

It’s very well constructed – small, smooth, solid, yet lightweight.

The LEDs are a missed opportunity. Sure, some consumers may be tempted to buy the XO for this novel feature, and perhaps those digging the gaming aesthetic will be entirely satisfied.

But wouldn’t the LEDs be so much better if they were synchronized with the music and functioned as level meter bars? Or frequency response meters? *Sigh*

The O filter button is another miss, with currently only two filter options (in correspondence, Hidizs mentioned that they were working on adding a third) that make very little audible difference. Playback or volume buttons would be a more useful choice.

The LEDs and X-O buttons make the XO stand out amongst its peers, but in every other way, the XO is a typical, if well-made, portable DAC/amp dongle.

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