Double-barrel!

PROS: single ended and balanced outputs, AK4493EQ DAC, supports 32bit/768kHz and DSD512, small compact size.

CONS: some overheating due to higher current draw.

The product was provided to me free of charge for the review purpose in exchange for my honest opinion.

Manufacturer website: Hidizs.  Available for sale directly or from authorized retailers.

---

Intro.

The demand for thumb-size usb DAC/amps went through a roller-coaster ride.  These were popular back in the days when sound quality of smartphones and laptops was sub-par, so it made sense to enhance it with external dongle.  Then, smartphone sound quality improved and the demand for these devices went down.  When some smartphones lost 3.5mm jack, it peaked up again, followed by going down due to popularity of TWS earphones and wireless DAC/amp dongles.  But not everybody is on-board with wireless audio connection, especially since you have to keep it charged and also, not every budget wireless dongle offers a balanced output.

In comparison to 2-3 years ago, today the demand for these small USB DAC/amp devices is not as high, but still exists, and some manufacturers continue to release new and improved models.  What makes some of these to stand out are higher end DACs, more powerful balanced outputs, and support for higher sampling rate audio.  Of course, if you choose to turn your smartphone into a DAP or to enhance your laptop with external audio interface, such device has to offer the improvement over your stock headphone jack.  Hidizs already released a few usb DAC/amps, with each having a better DAC and overall spec.  S9 is their latest release I’m going to look into.

Unboxing and Accessories.

Unboxing is straight forward, a small compact black box with Hidizs logo, model name, and device outline on the top, and a detailed spec on the back.  Inside, at the top, you will find S9 sitting securely in a foam cutout and accessories underneath of it.

Included with a device were a short 10cm type-c to type-c usb cable for use with a smartphone or another DAP, a longer 65cm type-c to type-c cable, and type-c to usb-a adapter so you can use these cables with your laptop or PC.  One thing to keep in mind, when connecting the cable, the side with Hidizs logo has to be connected to a source and the other side of the cable without logo has to be connected to S9.  You also get a warranty card and user manual.

As a bonus, Hidizs also included a clear plastic rear clip.  It securely snaps around S9 and adds a clip on the back so you can keep your phone in a pocket, secure DAC/amp on your belt or clothes and use the provided extended usb cable for convenience.

Design & Under the hood.

S9 is a little bit longer than S8, but it is still a relatively small device, measuring 59x19x8 mm and with a weight of only 11g.  Its one-piece CNC aluminum-alloy body, in either black or silver, feels solid, and according to Hidizs the rear cover material is glass so I assume the front is the same.  The front of the device also features Hidizs LED logo which lights up in different colors according to the sampling rate, yellow (DSD64/128), purple (DSD256/512), green (up to 96kHz), blue (192kHz), red (384kHz), and white (768kHz).

Bottom of the device has usb type-c connector which allows the use for different usb cables, including shorter or longer, or optional lightning cable of iOS devices.  Top of the device has 2 stacked headphones outputs, single ended 3.5mm TRS and balanced 2.5mm TRRS.  To keep the footprint of the device narrow, it was clever to stack these ports next to each other.  Each port has less than 1ohm output impedance, can support earphones and headphones with impedance of 8-150ohms, and 3.5mm has 90mW output while 2.5mm has 125mW.  Also, 3.5mm output supposed to be compatible with headphones that have in-line mic.  Unlike S8 with volume up/down buttons, there are no external controls on S9.

Under the hood of this mini usb DAC/amp, Hidizs packed AK4493EQ DAC which enables the support and playback of PCM 32bit/768kHz files and up to DSD512, and also wired and configured for both single ended and balanced operation.  Based on previously mentioned power output, there has to be some internal amplifier ckt, though no details were provided.  Considering AK4493EQ DAC, higher sampling rate support, and higher power output, the device does draw more current when connected to the host/source and also runs warmer to the touch.  That is one of the compromises you have to accept if you want a higher end spec which going to drain your phone/tablet battery a little faster.

Furthermore, according to Hidizs, their S9 DAC/amp has an upgradable firmware.  And, as already implied, it is compatible with Android, iOS, Windows, and Mac OS devices.

Page 2 – Sound Analysis, Comparison, and Conclusion.