Fosi Audio DS1 Review

Fosi Audio DS1 Review

3 March 2023 0 By Petros Laskis

Fosi Audio DS1 Review

A hidden gem

Pros: + Excellent sound quality with great technicalities
+ Musical and realistic timbre with minimum digital glare
+ Crystal clear and transparent
+ Powerful output suitable for full sized headphones
+ Dead silent and electromagnetically shielded
+ Balanced and unbalanced headphone outputs
+ Detachable cable
+ Multi Platform compatibility
+ Build like a tank
+ Hardware buttons for controlling the volume
+ Very competitive price

Cons: – Substantially heavier than the competition
– No MQA decoding (if you care)
– No accompanying application

Fosi Audio DS1 Review 

The review sample was kindly provided free of charge in exchange for an honest review.
I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links.
The price of the DS1 is $75.99 and you can order it from the Fosi Audio online shop.

Fosi Audio were kind enough to offer a 10% off promocode: CAR10DS1 for the readers of this article.


Fosi Audio

Fosi Audio might be unknown to you as it was to me so in order to get acquainted with them you can read the following information as derived from their website.
“An audio equipment company with a focus on HiFi sound, Fosi Audio was founded in 2017 by a team of engineers and music lovers with the objective of delivering high-quality audio products. After years of research and development, they have mastered the art of miniaturizing HiFi sound and bringing it to any space, big or small. Fosi Audio’s range of products includes speakers, amplifiers, headphones, turntables, and other hi-end audio equipment.
Their goal is to make audiophile-grade sound accessible to everyone and to further the advancement of music technology.”
Further information is available here.


Fosi Audio DS1

The Fosi Audio DS1 is a compact sized USB-DAC dongle that uses the ES9038Q2M DAC chip from ESS technology.
The amplification is handled by dual RT6863 op-amps by Ricore, in a fully balanced configuration, with a 120mW/32Ω(SE) and 220mW/32Ω (BAL) of power output while an auto detection system will switch to high gain mode for headphones with an impedance of 200Ω and above.

Built-in is also an independent jitter and phase noise active crystal oscillator for accurate audio reproduction.
From a technical point of view the Fosi Audio DS1 is pretty much identical to the FiiO KA3 or the Hidizs S9 Pro but it is the least expensive of the three.
It has both balanced (4.4mm) and unbalanced (3.5mm) headphone outputs and supports sampling rates up to 32bit/768kHz PCM, DSD512 but no MQA decoding while it is compatible with Android/iOS/Windows/Mac without the need to install any drivers.


Design and build quality

The rectangular chassis is made from a tin alloy and it has a rather interesting design with the rounded headphone plugs protruding from the main body.
The DS1 is built like a tank, it is relatively compact sized and not bigger than the competition but at 38g, is quite heavier from the FiiO KA3 which weighs 17.5g or the 23g of the iBasso DC06.
Except for the hardware volume control buttons there is also a notification LED that will light red for PCM and blue for DSD when in normal gain or yellow and magenta when switched to the high gain mode.



The DS1 comes with a type-C to C cable of typical quality with aluminum plugs and a USB A-C converter.


Listening impressions

The DS1 was left playing music for about 100 hours prior to listening tests.
For the evaluation I used various earphones and headphones like the FiiO FDX, Penon Vortex, Sennheiser HD660S and Focal Clear Mg among others.
The DS1 is dead silent without background noise or electromagnetic interference from the mobile phone.
Power output is among the best for a USB-DAC dongle and it didn’t have any problem driving all the full sized headphones mentioned above.
The following impressions include a comparison with the FiiO KA3.


Don’t let the humble price fool you, the DS1 offers a stellar sound performance that is on the same level with the competition like the FiiO KA3 and the Hidizs S9 Pro.
A reference linear frequency response with great transparency, crystalline clarity and excellent technicalities.
Regular readers will know that the ES9038Q2M is my favorite ESS DAC chip when implemented right and this is something that can be said for the DS1 as the implementation is truly good, at least as good as it can be for a passively powered USB DAC dongle.
It has the typical ESS fidelity and mirror-like source transparency but at the same time it manages to sound quite musical and engaging without artificiality or as giving the impression of a clinical and boring sounding DAC.
In that respect it is slightly more organic and analogue sounding than the FiiO KA3 with a touch fuller and weightier texture from the bottom to the top of the frequency range.
The bass is fast, tight, controlled and impactful with excellent definition and some great layering.
There is plenty of harmonic variety, especially in the critical mid-range which is distinguished by the colorful tonal palette and the fine articulation both for the vocalists and the instrumentalists.
The frequency integration is very good, the sound is blended and cohesive without too much of the accustomed ESS treble prominence.
The DS1 is one of the smoothest sounding ESS based DAC dongles I have tested with minimum digital glare and without too much brilliance.
It is still airy, detailed and open sounding with plenty of energy and a sparkle but it manages to sound controlled and realistic without making the notes become thinner than the ideal.
The DS1 is good sounding from both the balanced and the unbalanced outputs but the latter offers a slightly more expanded and wider soundstage with better holography and sharper imagining.


The DAC is music and headphone agnostic as it pairs well with everything and yields a very enjoyable listening experience with all types of music and all headphones, even brighter ones without sounding unforgiving and punishing.
Listening to all sorts of classical music was a real joy and the overall performance reminded me more of a mid range DAP rather than an entry level priced USB DAC dongle.


In the end

The Fosi Audio DS1 was a well hidden gem that has fortunately surfaced from obscurity and is trying to get the place it deserves in the overcrowded USB DAC dongle market.
It has an entry level price but it packs an advanced circuit design that is usually found in much more expensive competitors and it combines excellent sound performance with great power delivery, dual headphone outputs and hardware volume control.
The only real drawback is the increased weight but for the asking price, honestly I wouldn’t care that much.

Test playlist

Copyright – Petros Laskis 2023.