Hidizs S9

The Hidizs S9 is a compact digital-to-analog converter (DAC) and amplifier combination unit which connects to the source devices via USB-C. The S9 is the first Hidizs product I have reviewed since the AP60II digital audio player. Unlike the balanced output E1DA 9038S and the single-ended output E1DA 9038D which I recently reviewed, the Hidizs S9 incorporates both a single-ended 3.5mm audio jack and a 2.5mm balanced connection.
This review is also available on my blog: https://medium.com/bedrock-reviews/hidizs-s9-review-617eaeb2af6
The Hidizs S9 was provided to me for review by HiFiGo, where it is available for purchase starting at $109.
PACKAGING AND ACCESSORIES:


The Hidizs S9 comes in a rectangular black box featuring a line art illustration of the device on the top lid. Technical specifications for the S9 are provided in English and Chinese on the back of the box. In addition to the device itself, the box contains a manual, a 10% off promotional discount card for Hidizs’ webstore, a warranty card, and a quality control pass chit.
In its base configuration, the Hidizs S9 includes two USB C-C cables in different lengths. These cables are the single worst aspect of the S9 as a product. Contrary to both USB-IF specifications and common sense understanding of how USB-C cables are supposed to work, the S9’s included cables only work in one direction. One of the USB-C connectors has a purple coloring on the interior of the plug. This end needs to be plugged into the S9 in order for the transport device to power and recognize the S9. If the purple end is plugged into the transport device, the cable does not deliver power or data. I have tried using these cables with other USB-C DAC/AMPs, and the result is the same. Thankfully, the S9 works fine with generic, correctly-implemented USB C-C cables. The S9 also includes a USB-A male to USB-C female adapter, which I will note also breaks USB-IF specifications.
POWER DELIVERY:


Both of the Hidizs S9’s outputs are incredibly powerful. When the S9 is connected to a Windows PC, the SeeAudio Yume reaches usable listening volume out of the single-ended output at the 10/100 setting. The balanced output powers the harder-to-drive Moondrop S8 to a similar volume level at the 12/100 setting. Because I am confident that the S9 would blow out the drivers of a connected IEM at its maximum output level, it is hard for me to tell just how powerful it is. It is not clear to me whether the S9’s volume ramping model is different than that of the E1DA dongles I have tested, or whether the S9 is simply more powerful. I have not heard hiss with the 9038D even with multi-balanced armature in-ear monitors.
POWER CONSUMPTION:
The following power consumption measurements were taken while the Hidizs S9 was in use:

Windows PC (USB-A to USB-C)

Android Smartphone (USB C-C)
While power consumption appears to vary based on the paired transport device, it does not seem to vary based on whether the unbalanced or balanced output is being used. The power draw is higher than the balanced output E1DA 9038S Gen 3:

The power draw is also far higher than that of the gold standard for USB-C audio devices, the Apple dongle:

For this reason, I recommend using the Hidizs S9 either with a dedicated music transport device, preferably with a large battery, or with a PC.
The Hidizs S9 is mediocre in terms of heat management. While it does not get nearly as hot nearly as quickly as the Cozoy Takt C or xDuoo Link, it does get warm to the touch after a full workday of use. This is in contrast to the E1DA 9038 variants, which remain cool to the touch even if left connected for days on end with standby mode disabled.
SOUND AND CLOSING WORDS:

(3.5mm unbalanced output)
I have no complaints when it comes to the sound quality of the Hidizs S9. It sounds exactly the way a competently designed product at this price point should, which is to say, transparent.
If your intent is to listen to music and not gear, I don’t feel that either comparably priced E1DA 9038 variant is appreciably superior or inferior to the Hidizs S9 in terms of sound quality. If you are dead-set on listening to the source device, it is worth noting that unlike the 9038 variants, the S9’s digital filter selection is locked down. As I noted in my E1DA 9038D and 9038S reviews, I find different types of digital filters to sound audibly distinct from one another when holding all other conditions constant, including the transducer, volume, and specific musical passage. However, the differences I can hear between digital filters are subtle, and I personally would not purchase an E1DA product over the S9 purely on the basis of filter switching.
The Hidizs S9 differentiates itself from other options at this price point mainly through having both 3.5mm single-ended and 2.5mm balanced outputs on a single device comparable in both size and price to competitors that only offer one type of output. Importantly, S9’s unbalanced output is completely usable as opposed to being an afterthought. Some of the S9’s competitors offer superior heat management or more efficient power draw requirements, but it is difficult to argue with the value proposition the S9 presents.

The Hidizs S9 can be purchased below:
Hidizs S9 Balanced & Single-ended Mini HiFi DAC & Headphone AMP — HiFiGo

The device comes in a black box with an iridescent embossing. On the front, the company logo flaunts, the name of the DAC - S9 - and the outline of the device. On the bottom you can see the characteristics. Inside the "whistle" is used DAC AK4493EQ, connector - USB C. There are two colors to choose from: black and white.


The set is quite rich. Inside we will find:

• DAC itself
• 2 USB-C cables (one shorter, the other longer)
• Clip case
• Adapter USB-C to USB-A
• Various waste paper

The device itself has a relatively small size, a steel frame and plastic (and very quickly smudged) front and back panels. On one end there is a type-c connector, on the other - 2.5mm (balance) and 3.5mm outputs. There are no buttons or other controls. In general, the device looks rather strict and sipaty. As for me, it will not be a shame to even wear such a jacket. By the way, the logo is highlighted (at night, I think it will be annoying).


Unfortunately, I didn't like the device at all in terms of sound. Absolutely sluggish and boring low frequencies. The strings sound boring, there is a lack of overtones. On heavy music, guitars lack aggression. For me personally, listening to such a sound is boring and uninteresting.

In general, to my ear, the device is completely undeserving of attention. Very sorry. It looks like the only thing that Hidizs really does really well is their AP100 player. Then they turned the wrong way. In any case, this was just my opinion about this device.

Comparison with xDuoo Link 2:
At the same time with xDuoo I had Hidizs S9 and was able to compare them with each other. The strongest part of Hidizs is high frequencies, but mid and bass are the weakest. When choosing between these two devices, I will definitely prefer a product from xDuoo. It is close to me in spirit in terms of sound, it is more functional as a "whistle", and they cost about the same. In any case, it's up to you to decide.

Both devices are available here for about the same price.

TL;DR
If you don't use demanding earphones, you can use this as your all-in-one DAC/AMP.
No need for separate desktop/portable DAC/AMP.

Package
S9, 2x usb-c cable, full usb to usb-c adapter, pocket clip

Build
Aluminium. Smooth, cool and clean. Feels nice to touch.

First thought/What to expect
Velvet Sound because it's AK.

TEST TOPIC
1. Sound Quality (SQ)
2. Power Consumption
3. Heat

TEST EQUIPMENT
Android micro-usb, Android usb-c, PC Linux. You'll probably need micro-usb to usb-c adapter OTG adapter for older mobiles. PC setup done with the provided accessories from the box.

SOUND QUALITY
Very good sound quality, clear without distortion. Can't notice the difference to desktop setup or without using DAC/AMP but I prefer the S9 sound output. Huh? Eh? Whuttt... Anyway it's probably a brain thingie.

POWER CONSUMPTION
ANDROID
~63 minutes => ~15% battery consumption on Hiby App on Android micro-usb.
~46 minutes => ~8% battery consumption on Hiby App on Android usb-c. (may not be accurate because test got interrupted)
AIMP also works.

LINUX
Doesn't apply but let me say a few things. Linux support is truly good. Plug and play, completely bypass the OS master volume and interacts directly with the audio player volume.
HEAT
Using Hiby, it runs cool, barely warm after ~1 hour.
Using AIMP, the thing heats up fast. It gets hot. Probably becauses AIMP doesn't have the USB DAC support?

Closing thought
Does the job as expected. For the price it's definitely worth it for the DAC/AMP + 2 connections. 2.5mm connection will be tested later maybe. Too bad can't really do more demanding tests since no nitpicky/demanding cans/earphones. So where's the Velvet?

Verdict
5/5 as far as SQ goes, but overall 4.5/5.