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Product: Fosi DS2 - headphone amp & HiRes DAC
Manufacturer: Fosi Audio - China
Approx. price: ±€70
Reviewer: Lucio Cadeddu - TNT-Audio Italy
Reviewed: july, 2025

Foreword

After testing the direct competitor iFi GO link Max, it's time to test the DS2 by Fosi Audio. This is a new version of the DS2 model but, as is the weird unconventional habit of some Chinese companies, the name of the model remains unchanged (it appears as DS2 2024 on the official website). It is a dongle DAC/headphone amplifier that promises to improve the audio output from smartphones, computers and tablets, especially if they do not offer a traditional headphone output.

A closer look

The DS2 by Fosi Audio undergoes a profound revision compared to the previous model, so much so that the DAC chip also changes, now it's a double Cirrus Logic CS43131, a chipset that also includes a power section to directly drive the headphones. The claimed power is 130mW on 32Ω on the single-ended output (unbalanced 3.5 mm) and a good 510mW on the S-Balanced output, still on 32Ω. These figures are slightly higher than those of the competing iFi Audio GO link Max. The S/N ratio is 130dB, the THD+N is 0.0001%, the frequency response between 20 and 20kHz is within ±0.5dB. It can handle PCM streams up to 32bit/384kHz and DSD up to 256. As in the case of the iFi GO link Max, a series of LEDs of different colours indicate the type of digital stream input. With respect to the impedance of the headphones that can be connected, a conservative range between 16 and 300Ω is suggested, even if the datasheet of the Cirrus Logic chip used explicitly speaks of loads up to 600Ω.

The extruded aluminium case has no sharp edges and houses two very useful switches that adjust the volume in 60 steps (with memory), a feature absent in the iFi Audio GO link Max. It works without the need for additional drivers on all operating systems and on all phones. As usual, on some smartphones it may be necessary to activate the OTG output from the settings menu. A good quality USB-C cable is supplied, while the standard USB to USB-C adapter is missing, in case you want to use it with a computer that only has standard USB sockets. The cable for (Apple) Lightning sockets is also missing, and it's sold separately for 15€. The component is covered by a 24-month warranty.

Listening notes

I performed the tests with both smartphones and computers, even under Linux operating systems and I did not encounter any compatibility or interface problems. There is no need to install proprietary software or apps.

The most logical comparison to perform is with the iFi GO link Max, a competitor of the same price (slightly more expensive, actually). First of all, the power output: the Fosi DS2 sounds louder even on the unbalanced output and with low-impedance headphones. As for tonal balance, the two devices sound quite different, the iFi Audio being more educated, extended and open in the high range, while the Fosi is fuller in the mid and mid-bass range. In the bass range the two DACs are essentially equivalent. The harmonic richness is good in both, but the Fosi DS2 seems to give more realism to acoustic instruments. On string instruments, in particular, it highlights the instrument's natural breath, and hence it improves presence and naturalness. Even saxophones and trumpets appear harmonically richer.

Dynamically the Fosi has an edge, it is possible that the higher power output plays some role in the more demanding musical passages. It also sound punchier and faster. In this area, the difference is not subtle.

Finally, for what concerns the (unpleasant) sensation of sound inside the head I haven't noticed any differences and certainly both dongles manage to reduce this annoying effect, compared to listening on the standard headphone output of a cell phone or notebook.

Remarks & Complaints

Manufacturing & Finish.
The DS2 is very well made, sturdy and easy to use. The connection cable is removable and replaceable, while on the competitor iFi GO link Max it is fixed. The USB-C connector on the iFi is gold plated, while it is a standard connector on the DS2. It is a little larger in size, compared to the iFi competitor, and obviously it's also a little heavier, but nothing that limits its portability in any way.
Sound.
No negative aspects to report: it sounds strong, dynamic, harmonically rich and precise. It is free from any artificial “softness” in the high range, but for this very reason realism is one of its strongest virtues. If you are looking for a DAC / headphone amp that forgives some harshness of lesser recordings, this DS2 is not for you. Garbage in, garbage out.

Conclusions

While other Fosi Audio devices stood out from the direct competition also because of the significantly lower cost, the DS2 price is aligned, and the price difference with the competitor iFi GO link Max is negligible. This probably reflects the care taken in the choice of components and in the construction, aspects that are also found in the performance, which is of an excellent level.

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© Copyright 2025 Lucio Cadeddu - direttore@tnt-audio.com - www.tnt-audio.com

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