Hidizs S9 PRO Copper Limited Edition
Copyright Hidizs 2021

Hidizs S9 PRO Copper Limited Edition Review

The Hidizs S9 PRO Copper Limited Edition is a 500 unit run of the S9 Pro featuring a unique red copper material finish. It is priced at $149.

Disclaimer: The Hidizs S9 PRO Copper Limited Edition sent to us is a sample in exchange for our honest opinion. We thank the team at Hidizs for giving us this opportunity.

To read more about Hidizs products we have reviewed on Headfonics click here.

Note, this 2-page review follows our new scoring guidelines for 2021 which you can read up on here.

Hidizs S9 PRO Copper Limited Edition
Hidizs S9 PRO Copper Limited Edition
The S9 Pro Copper Edition is a luxurious variant of the S9 Pro. From its regal appearance to its robust chassis, the extra $50 the copper commands are well worth it. However, the increased weight from its solid aluminum chassis does slightly diminish its ability to operate as a lightweight, ultra-portable DAC/amp.
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The release S9 PRO Copper Limited Edition should be of no surprise. Hidizs has a track record for re-releasing aesthetic variants of past products such as the AP80 Pro Copper Edition.

Internally, nothing has changed apart from some quality-of-life upgrades in the chassis in which it inhabits; the S9 PRO Copper Limited Edition has taken similar footsteps. Any noteworthy changes are purely visual or build-related.

While the novel inclusion of a high-density CNC aluminum shell is a welcomed addition to an already good product, does it warrant the extra $50 dollar premium?

Hidizs S9 PRO Copper Limited Edition
Copyright Hidizs 2021

Tech Highlights


The S9 PRO Copper Limited Edition (like the S9 Pro) proudly boasts the ever-so-reliable ESS9038Q2M DAC, a 2 channel DAC designed by industry favorites, ESS Technologies. As mentioned previously in my S9 Pro review, the S8 can pump out 100mW into 32 ohms from its 3.5 single-ended out, and 200mW into 32 ohms on its 2.5mm balanced out.

Moreover, the S9 PRO Copper Limited Edition boasts some impressive measurements under the hood (Total harmonic distortion), at 0.0006%@32ohms in the 3.5mm out, and 0.0012%@32ohms.

Lastly, the S9 PRO Copper Limited Edition is compatible with all digital music formats, including the data-heavy DSD-64 and MQA. For more technical information, feel free to refer to my previous S9 Pro review.

Hidizs S9 PRO Copper Limited Edition
Copyright Hidizs 2021


The S9 PRO Copper Limited Edition shares an identical form factor to the S9 Pro. Structurally, there are no observable changes, and it still retains the S9 Pro’s distinctly monolithic appearance.

The lack of physical volume controls and the previously discussed balanced and unbalanced outputs are still situated at the same points on the S9 PRO Copper Limited Edition.

However, as the name implies, the S9 Pro Copper Edition adopts a copper colorway (thanks, captain obvious). Subjectively, the S9 PRO Copper Limited Edition has an ostentatious demeanor that gives it an expensive allure.

The borders of the S9 PRO Copper Limited Edition have an evenly-brushed finish, followed by a polished top and bottom of the unit.

Combined with a substantive increase in weight, one would expect that its concomitant price tag would be significantly higher, epitomizing the oxymoronic concept of affordable luxury. Mid-fi audiophiles can rest easy, knowing that they don’t have to sell a kidney to afford the next big product.

However, by opting for a high-density CNC aluminum case, there is a marginal increase in its weight from 11g in the original S9 Pro to 25g.

These impractical changes limit its ability to be used outdoors as a portable DAC/Amp carry, especially if the S9 PRO Copper Limited Edition is left to dangle from your back pocket. This may or may not be a huge caveat depending on how it’s being used.

Battery Life

The S9 PRO Copper Limited Edition does not have its own independent battery; power is drawn efficiently from the source. However, it accelerates battery drain by 25-30% across most portable smart devices; battery drain is solely dependent on which headphone out is being used more.


There are only 3 inputs and outputs present; a USB-C connector at the rear of the unit, and a 2.5mm balanced and 3.5mm output right below at the other end.


Unfortunately, my previous complaint on the S9 Pro had not been addressed; there are no step-by-step controls independent of the source connected to it. A small complaint, albeit one that should be addressed. More control affords the user more flexibility.

Hidizs S9 PRO Copper Limited Edition

Packaging & Accessories

There is a clear running theme throughout the course of this review:  nothing much has changed! And that sentiment still stands in the packaging section.

The S9 PRO Copper Limited Edition comes in a professional cardboard box with an image of the S9 Pro Copper Edition adorning the top lid with a glossy finish.

Inside the package, you’ll find the unit itself, every USB-C cable permutation for multiple use scenarios (Apple, Android), a female USB-C to male USB adapter, a plastic clip for pocketable use outdoors, and multiple instruction manuals.

Leaving no stone unturned, the S9 PRO Copper Limited Edition covers all standard audiophile bases.

Sound Impressions


As mentioned previously, there are no sound-quality changes between the S9 PRO Copper Limited Edition and S9 Pro: both units are one and the same. They share the same ESS DAC, the same measurements, and the same power output. As a result, nothing else can be said about its performance.

Nevertheless, to briefly surmise: the S9 Pro is an excitable DAC/Amp that tastefully accentuates the “striking section” within the FR: the mid-bass and upper midrange.

The S9 PRO Copper Limited Edition errs on the side of flat/neutral without overplaying the “neutral” card. Thuds and kickdrums appear more pronounced with an authoritative presence.

Depending on what is being paired with the S9 Pro, occasional treble-glare does present itself on brighter headphones, with a slight over-emphasis on the ‘honkier’ peaks in poorly mastered tracks.


Because of the S9 PRO Copper Limited Edition’s stringent focus on the sharper or distinct elements in the FR, the timbre can come across as wonky or unnatural when paired with transducers tuned towards a flat or neutral response.

However, speed and tactility are its fundamental strengths; users’ mileage may vary. For example, acoustic recordings featuring even-harmonic warmth appear are weakened by marginally exasperated treble.

At the same time, however, a more prominent treble enhances the sharper transients exclusive to horn sections.

Staging & Dynamics

At lower volumes (25% of my Samsung S21), the S9 PRO Copper Limited Edition displays an excellent dynamic range, capturing subtle changes and gradual transitions between silent and loud passages of music at low volumes.

As briefly alluded to earlier, punchier mid-bass bumps and energetic treble peaks are slightly enhanced for an excitable juxtaposition between both elements in the FR.

Hidizs S9 PRO Copper Limited Edition



As alluded to previously in my original S9 Pro review, the Hidizs S9 Pro (and the Copper Edition) offers the same power output (100mW into 32Ω from its SE output, 200mW into 32Ω from its balanced output).

The S9 Pro does not struggle with high impedance loads. The Sennheiser 58X Jubilee Edition is a 150Ω full-sized, open-back dynamic driver headphone. At less than 50% digital volume on my Samsung S21 as my source, the Jubilee had ample headroom; notes did not sound compressed, nor did distinct regions in the FR bleed into one another.

On the extreme end of things, the infamous Tin HiFi P2, a planar-magnetic IEM with a notoriously low sensitivity rating did not fare well on the S9 PRO Copper Limited Edition. It is important to consider the limited power-draw that dongle DAC/Amps can derive from a smart device.

For safety reasons, there are internal caps instated by tablet/smartphone manufacturers. Therefore, it would be remiss to expect the S9 PRO Copper Limited Edition to compete with the likes of dedicated portable Amp/DACs. Simply put, there are several technological restrictions that delimit dongle DAC/Amp manufacturers from increasing power output.

Hidizs S8

Select Comparisons

Hidizs S8

$79.99 USD


The S9 PRO Copper Limited Edition is the re-iteration of the S9 Pro, and S9 Pro is a re-iteration of the S8. Do not be fooled however, the S8 is a legacy device that still stands the test of time.

Comparatively, the S9 PRO Copper Limited Edition power output is threefold that of the S8’s. The S8’s dated CS43131 DAC is simply no match for the technologically advanced ESS DAC implementation on the S9 Pro Series.

Like the original S8, the S9 Pro is compatible with all smart devices. As discussed, the removal of the independent volume controls is a step in the wrong direction.

To activate the S8, users are to plug in their earphones or headphones into its 3.5mm output, prior to connecting it to the source device. This problem is no longer prevalent on the S9 PRO Copper Limited Edition.

Overall, the S9 Pro has taken many steps forward, and one step back in terms of utility


Visually, the S9 PRO Copper Limited Edition is a sharp deviation from the design language adopted for the S8.

Firstly, the S9 Pro Copper Edition is lengthier. Secondly, it features a 2.5mm balanced output which the S8 lacks. Most importantly, the S9 PRO Copper Limited Edition is adorned with a single USB-C port


Both units feature Hidizs’s signature sonic profile. The only striking difference is a slightly slubbier bass response that accentuates a lower sub-bass shelf, and a slower-note decay. Consequentially, bass/baritone regions or instruments begin to meld into another.

Volume-wise, the S9 Pro requires fewer steps when paired with the Sennheiser HD58x. The S8 unfortunately, simply lacks the same driving power. The S9 Pro reflects Hidizs’s measured approach as it improves upon its older portfolio of products.

Hidizs S9 PRO Copper Limited Edition

Hidizs S9 Pro

$104.00 USD

Technical & Performance

Same internals, different dressing; there are no technical or performative differences between them. However, a strict side-by-side comparison of both models would highlight the few differences that make the S9 PRO Copper Limited Edition distinct from the S9 Pro.


Instead of discussing “performance”, this section focuses on the glaring differences which make the Copper Edition unique to the S9 Pro. For starters, the sharp increase in weight is either a bane or boon.

On the one hand, the extra weight gives the S9 Pro Copper Edition a satisfying heft, akin to the ostentatious offerings from boutique audio brands such as Astell and Kern. Aesthetically, the S9 Pro’s copper colorway and high-density, aluminum chassis exudes quality and class like no other DAC/Amp.

However, as an everyday carry device, the extra heft places undue strain on the connecting cable between both the DAC/Amp and the source.

To some, this may come across as a minor grievance that does little to detract from your experience with the device. At the end of the day, it boils down to how each user plans to incorporate the device into their daily life.

Our Verdict

The S9 Pro Copper Edition is a healthy re-interpretation of the S9 Pro. While it does nothing to improve upon its subjective performance the S9 Pro Copper Edition is a welcomed addition to an ever-growing family of Hidizs DAC/Amps.

Hidizs S9 Pro Copper Limited Edition Specifications

  • Transmission Interface: USB Type-C.
  • PCM Decoding Support: Up to 32Bit/768kHz.
  • Native DSD512 decoding support.

Output Parameters (Single-ended 3.5mm)

  • Rated output power: 100mW@32Ω.
  • Frequency response: 20Hz-50kHz.
  • SNR: 120dB.
  • Channel Separation: 80dB.
  • THD+N: 0.0012%.

Output Parameters (balanced 2.5mm)

  • Rated output power: 200mW@32Ω.
  • Frequency response: 20Hz-50kHz.
  • SNR: 119dB.
  • Channel Separation: 118dB.
  • THD+N: 0.0006%.

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