Hidizs ST2 Nebula – type-C DAC & IEMs as a convenient package

Hidizs ST2 Nebula – the new great option for audio fans with a smartphones missing a dedicated analog audio output and for those, who don’t like cumbersome desk setups with the external DAC/AMPs. All-in-one, universal solution that combines everything – high-quality IEMs, type-C DAC/AMP and even HD mic with phone control button. Time to test whether such bundle does the trick of delighting a demanding user, performing good in both – audio and everyday general use.

Hidizs is giving away ST2 Nebula bundle and other prizes for free. Join this draw here: LINK

You can get the least price and support this product on Kickstarter: LINK

Kickstarter Launch Date: December 19th, 2024, at 10:30 AM (EST)

Pricing Details:

ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units)
ST2 PRO Nebula (Early Bird): $49.00
USB-C DSP 0.78mm 2-pin/MMCX Earphone Cable (Early Bird): $36.00

Being a fan of single dynamic IEMs, I am glad that Hidizs intends this bundle in particular. Not limited to single type of IEMs – you can use any model of your choice with 2pin / MMCX connector to use with this DAC/AMP on a cable – but the supplied IEMs are the most universal in its tuning, shape, performance and price. Single DD, 10mm DMC lightweight diaphragm, large resonance chamber and H-2019 target curve – what can be more convenient for most of the ears? What I mean by that is that Hidizs made a move to present something that can go easy on every person, no matter which smartphone/laptop/pc/tablet and OS he uses, no matter the music genre he or she likes and no matter what size and shape of the ears he/she has. Nebula should fit and satisfy any. Type-C brings the possibility to connect to most of the modern devices, custom shape is the most versatile, H-2019 curve and dynamic diaphragm combination makes music smooth and crosses out high peaks. Plus the ability to use mic and watch videos with zero-latency… It is only left to try out and find whether everything declared goes flawlessly.

Hidizs ST2 Nebula specs:

IEMs:

• 10mm DD, dual magnetic circuit diaphragm
• resin + aluminum alloy etching shells
• freq.range 20Hz-40kHz
• 0,78 2pin/MMCX ports
• inline control + HD mic
• sensitivity 108dB
• impedance 32Ohms
• weight 7g

DAC/AMP

• ES9281AC PRO
• 32bit/384kHz / Native DSD 64/128
• MQA 8X
• distortion 0,0012%
• snr 118dB
• dynamic range 122dB
• ch.separation 63dB
• output power 70+70mW

ES9281AC PRO used in Hidizs type-C DAC is the flagship SoC with integrated USB. It is not that common among its rivals and let’s say – above the line. Although, what matters more than the chip itself – is the integration and circuitry around the chip that can either disclose SoC potential or place it below the worst products. Hidizs team has large experience of building compact audio products that allows them to go the first way – build a tiny DAC/AMP that sounds like a DAP or even some desktop devices. But I’d leave it for the sound test section.

Box contents, design and build quality:

Nebula fits to small black box, traditionally with silver shiny names, logos and product pics. Two layers inside, one to secure IEMs in place and additional pouch with handy opening mechanism found underneath. Cable is located inside this pouch. Personally, I don’t like that the pouch has some soft cloth inside as the velcro tape around the cable is quite sticky… Anyway, it does it job of keeping IEMs scratch-free in real life. Additionally, there are couple of small bags with a set of silicone ear tips and USB A -> USB C adapter.

Having such adapter means that Nebula has everything you need to use it with PC/laptops that don’t feature type-C ports.

Always been a fan of transparent materials used in the design of electronic equipment. ST2 features not only transparent IEM shell to see its neat cable management and channels but also the body of DAC/AMP is a combination of aluminum and glass. This opens its internal circuitry for observation and brings the additional feature: LED sample rate indicator. This has been a distinctive feature across all Hidizs products for a long time now. Not saying that it is very informative, but you can easily differentiate SD/HD track sample rate, at least.

IEM shells are available in dark / light options, all equipped with 0,78mm/2pin ports for cable and have long protruding output nozzles, ending up with protective mesh.

As far as I understand, Hidizs would also make ST2 Nebula cable with integrated DAC/AMP available separately, in two versions: 2pin and MMCX types of connectors. This would allow make any IEMs compatible with most of type-C devices.

Cable that came in my bundle is 0,78/2pin type, wrapped in textile yarn, has flexible ear guides, equipped with HD mic and inline remote button and ends with the aluminum DAC/AMP shell. Feels sturdy enough to live long and serve its purpose for many IEMs that I would like to try out in such scenario in the future.

In use:

Couple of words here about ST2 Nebula operation: as already mentioned – it is compatible with any USB type-C equipped device that has the ability to recognize external DAC. Windows, Mac OS based desktops or laptops, perhaps Linux based platforms, Android/iOS tablets and smartphones with OTG support… Hidizs says that only IPhone 15 and later are compatible (I am not Apple fan – only IPhones starting from 15 has type-C????). Even if you don’t have type-C, you can try to use USB A -> type-C adapter or some USB hub. Even Hidizs AP80 player running Linux-based HiBy OS has successfully recognized Nebula as an external DAC.

Since this device is passive (doesn’t have a battery) – it relies on USB power. Not a big deal for any device, except the smallest ones like Hidizs AP80 DAP which recognizes and utilizes USB DAC perfectly but the battery drain goes faster. What I’ve noticed is that Nebula gets quite warm, especially with HD quality tracks. About 42 deg.C after 15-20 minutes of indoor use. SD quality doesn’t have such impact. Anyway, 42C is nothing to worry about. Just having a warm little powerhouse in your pocket. Power consumption is about 50-55mA @ 5V.

Sound quality:

Since IEMs are tuned accordingly to H-2019 curve, they produce smooth sound with no accents or unexpected peaks. This is a slight V-shaped tuning with rich but slightly congested lows, dynamic and tight mid bass, natural and mellow mids and balanced treble. Amount of details and resolution are not overwhelming but IEMs still sound clear and have well defined instrument spacing and their layering. Nothing gets lost in the mix, each small detail is present. Stage depth and width are moderate but not too tight. I would say that those IEMs belong to 70-120$ single DD class, no more and no less. Perhaps, the least detailed here is the treble – lack of lightweight airiness and slight tendency to hisses. Although, this is compensated by the overall good balance and its timbre which make those IEMs sound natural and immersive. Was surprised how good it handled most of the music genres, including rap and hiphop, but noticed a bit of harsh high notes in heavy metal.

DAC/AMP SoC on its own is unexpectedly powerful for the bundled pair of IEMs – even 30% volume is quite a lot. I even tried Hidizs MP143 planars to pair with it and IEMs felt decent with this level of power output. Didn’t notice any obvious coloration or accents in comparison to Hidizs AP80 player – quite close. The only difference is that AP80 DAP is pushing slightly more noticeable texturing across the ranges and a little bit more delicate on treble. Such details are only apparent after long A/B testing in quiet surroundings, not on the go as intended by Nebula nature.

HD mic works fine on my Xiaomi smartphone but I wished that it would be a little more sensitive and less prone to incoming noises. It captures voice clear and loud indoors but might suffer from the surrounding environment and rubbing against clothes outside.

Conclusion:

Hidizs ST2 Nebula is good, convenient and universal bundle of IEMs and type-C DAC/AMP designed to be used with most of type-C equipped devices, no matter indoors or on the go. IEMs are both – comfortably tuned and ergonomically fit while DAC is cross-compatible between different OS, devices and IEMs, as well as powerful enough to drive even more demanding planars. Therefore, buying such bundle we get 2 devices at once that can be used independently. But I like the synergy it produces as a bundle and the intention of Hidizs to create the balance between the connectivity, sound quality and convenience of everyday use of this combo. I would leave my planars and DAP for more dedicated listening while ST2 Nebula bundle can join my smartphone when I leave home.

Hidizs is giving away ST2 Nebula bundle and other prizes for free. Join this draw here: LINK

You can get the least price and support this product on Kickstarter: LINK

Kickstarter Launch Date: December 19th, 2024, at 10:30 AM (EST)

Pricing Details:

ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units)
ST2 PRO Nebula (Early Bird): $49.00
USB-C DSP 0.78mm 2-pin/MMCX Earphone Cable (Early Bird): $36.00