FOSI S3 Balanced Streamer Review

[Lowfi]

This is a review and measurements of the Fosi S3 streamer and DAC. It was sent to me by the company and costs US $260.
View attachment 527172
The labels are hard to read but otherwise, the unit fits the "ID" of other Fosi products. What put a smile on my face was not the front, but the back:
View attachment 527173
Did not expect the XLR balanced outputs! There is also S/PDIF out allowing you to use an external DAC. Inclusion of Trigger out to power on your amplifier is also a very nice touch.

There is an app to control it as well as a remote control. Power is provided by a small switching power supply, double the size of the typical mobile phone charger.

Support for streaming protocol at this point is limited. Roon is waiting for certification. And Chromecast in my testing truncated to 16 bits. Airplay and UPnP is provided the latter of which I used for my testing.

Fosi S3 Streamer Measurements
As usual, we start with our dashboard, streaming UPnP from my desktop over Ethernet:
View attachment 527174
I tested Toslink input and got the same excellent results:
View attachment 527175
View attachment 527176

Dynamic range is very nice for class:
View attachment 527177

As is Multitone intermodulation test:
View attachment 527178

Noise floor in jitter test is not state of the art but again, very good for this category of product:
View attachment 527179

Finally, we have our typical filter roll off with excellent attenuation above 24 kHz for CD sampling:
View attachment 527180

Since my analyzer can't control streaming devices, this is all that I could (easily) test.

Conclusions
I must say, I did not expect Fosi to jump into streaming domain given the heavy software burden that brings with it. They have licensed the core technology which eases entry but also causes delays in bug fixes and feature enhancements. We see some of that effect here but what is there is quite solid. Measured performance is excellent as is support for my favorite, balanced output. Value is quite high given the price point.

I am going to give my recommendation to Fosi S3 streamer. I would have ranked it the highest levels if it had support for Roon already available.
----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Thank you Amir for the review. I am considering using this device as a preamp and would be connecting my Fosi Box X5 to the RCA inputs for vinyl. Should I expect a noise/ distortion penalty? Related, shouldn’t Topping be offering a top flight phono pre? If anyone can make a nice quiet phono stage it would be Topping, no?

 

[morillon]

Bingo...

I am happy with the several WiiM units I have around the house despite somewhat lower technical performance - the app works well and they connect to my home network and everything pretty cleanly. To me that functionality is the prerequisite for a streamer. If I were getting into multi room streaming today, I'd have a close look at the S3, with a critical eye to app functionality above all. Transparent sound isn't worth much if the streamer won't actually play stuff the way you want it to. I assume it's good in that regard but I agree it's the top concern for anything in this category.

Glad to see Fosi going after this market - if nothing else it will keep WiiM honest.

Mini or "pro"?

What's surprising, actually, is the choice of D/A conversion. FOSI seems to have simply started from the same base as the "Plus," which is already a few years old ( summer 2023)... and therefore remains in the same category as the Ultra and the "Plus"...*
I don't understand...
FOSI had the opportunity to really drive the point home compared to Wiim, for example (same price range), by switching to more ambitious, even double-sized, chips...
FOSI being more experienced in audio than Wiim...

They stuck to the rather "marketed" presence of "XLR" and "1612"... (the Ultra being ESS/1612)...

when most people will use unbalanced... which hasn't been tested here...shame...


*That's what's surprising... Or ...
that Wiim hasn't yet realized the sometimes technical but especially commercial appeal of balanced "xlr" for the general public.
;-)

 

[Ruediger]

The hard work just started for them. Bring software that can take on WiiM.

 

[Billy Budapest]

Voted “great” for a myriad of reasons:

1). Connectivity options are great in such a small package, and the performance is great given the functionality and the small amount of space to cram radios, processing, D/A conversion, and analog circuitry and still achieve excellent, not far from SOTA performance;

2). Functionality is only going to get better—read the Fosi web page detailing next month’s changes coming to the app, and also pending Roon licensing.

For a very small, inexpensive box, you can’t ask for much more. Equivalent or better than the WiiM Pro Plus for a cheaper price. I almost wish I hadn’t purchased the Pro Plus a few months ago.

 

[Billy Budapest]

Bingo...

I am happy with the several WiiM units I have around the house despite somewhat lower technical performance - the app works well and they connect to my home network and everything pretty cleanly. To me that functionality is the prerequisite for a streamer. If I were getting into multi room streaming today, I'd have a close look at the S3, with a critical eye to app functionality above all. Transparent sound isn't worth much if the streamer won't actually play stuff the way you want it to. I assume it's good in that regard but I agree it's the top concern for anything in this category.

Glad to see Fosi going after this market - if nothing else it will keep WiiM honest.

The WiiM App gets a big fail from me for the WiiM sub integration. Just terrible. And the manual lists the wrong colors and wrong behaviors of the LED on the sub. Otherwise, the WiiM sub is a very good product if you have a small room.

 

[Billy Budapest]

These broad claims better be based on facts, not opinions. At least try it yourself to see if it is true for you. Until then, here is published, controlled listening tests of SBC:

View attachment 527357

It only achieves transparency in one track, the easy classical one.

Here is AptX:
View attachment 527358

In my own ad-hoc listening tests, SBC is better than both AAC and Aptx. Only LDAC beats it which is not always supported at both ends.

Just what do the makers of AptX (Qualcomm) and AAC (Dolby Labs) think they can do better than SBC? I’ve never heard a difference. I mean, SBC even supports a higher bit rate than AptX (albeit only slightly), 551 kbit/s vs 529 kbit/s. I’m not sure SBC is still limited to 48kHz sample rate (vs 96kHz for AAC and AptX).

 

[valcon]

Graphic:


And here's confirmation that it's indeed fixed frequency, fixed Q (click the arrow to see the full message):

Thanks for clarifying!

 

[Jasperous]

I use the Hiby music app with eq and 10 band peq (with Qobuz or Tidal) on my Android phone and a 3-5 meter long usb cable between my phone and dac. I get lossless playback easily and cheaply. Sometimes I use bluetooth connection between my phone and dac (LDAC). I don't see why I should spend money on a separate streamer.

Then don’t spend it on a steamer, but many of us have secondary systems and the convenience and simplicity of a streamer are the features we need

 

[Chanur]

I could definitely see me getting one of these for a secondary system in another room.

 

[xanalog]

I think I am going to wait for the "Plus" version,

... the version that will include USB-C (I had forgotten that they had forgotten).

Where is the USB-C I/O?

 

[jimroge]

If only it featured filters for sub integration, it be a home run.

 

[David Marksberg]

This is a review and measurements of the Fosi S3 streamer and DAC. It was sent to me by the company and costs US $260.
View attachment 527172
The labels are hard to read but otherwise, the unit fits the "ID" of other Fosi products. What put a smile on my face was not the front, but the back:
View attachment 527173
Did not expect the XLR balanced outputs! There is also S/PDIF out allowing you to use an external DAC. Inclusion of Trigger out to power on your amplifier is also a very nice touch.

There is an app to control it as well as a remote control. Power is provided by a small switching power supply, double the size of the typical mobile phone charger.

Support for streaming protocol at this point is limited. Roon is waiting for certification. And Chromecast in my testing truncated to 16 bits. Airplay and UPnP is provided the latter of which I used for my testing.

Fosi S3 Streamer Measurements
As usual, we start with our dashboard, streaming UPnP from my desktop over Ethernet:
View attachment 527174
I tested Toslink input and got the same excellent results:
View attachment 527175
View attachment 527176

Dynamic range is very nice for class:
View attachment 527177

As is Multitone intermodulation test:
View attachment 527178

Noise floor in jitter test is not state of the art but again, very good for this category of product:
View attachment 527179

Finally, we have our typical filter roll off with excellent attenuation above 24 kHz for CD sampling:
View attachment 527180

Since my analyzer can't control streaming devices, this is all that I could (easily) test.

Conclusions
I must say, I did not expect Fosi to jump into streaming domain given the heavy software burden that brings with it. They have licensed the core technology which eases entry but also causes delays in bug fixes and feature enhancements. We see some of that effect here but what is there is quite solid. Measured performance is excellent as is support for my favorite, balanced output. Value is quite high given the price point.

I am going to give my recommendation to Fosi S3 streamer. I would have ranked it the highest levels if it had support for Roon already available.
----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Considering that it includes ADC and seems to not require an 'app' to access basic functions I'd say it looks fantastic. Plug in phono or tape deck or tuner or...

 

[David Marksberg]

Considering that it includes ADC and seems to not require an 'app' to access basic functions I'd say it looks fantastic. Plug in phono or tape deck or tuner or...

 

[Guddu]

Considering that it includes ADC and seems to not require an 'app' to access basic functions I'd say it looks fantastic. Plug in phono or tape deck or tuner or...

Well... you will have to run the initial setup through Fosi Audio app to even pair the included bluetooth remote before using it and keep track of volume level (if you want).

 

[soundofsilence]

What is the current recommended streamer with balanced outputs?

 

[Corvuscorone]

Then don’t spend it on a steamer, but many of us have secondary systems and the convenience and simplicity of a streamer are the features we need

I understand that, I was just thinking about this for myself. Especially since this Fosi doesn't have PEQ and Bluetooth is only SBC and AAC. At home I only have a SIM card-operated router for wireless network, which is quite weak. I used to use Chromecast audio, but I always had problems with it due to disconnection. That's why I ended up with the current system, which I can use with different lengths of cables in all the rooms where I have stereos with a separate dac.

 

[jareinertson]

I'm afraid I am a loss as to what streamers are for? Seriously I cannot see a reason.

Seeing as you need you phone to run the control app, why not just have a decent, modern Bluetooth receiver and run your streams from your phone?

Most homes don't have ethernet wiring, so how many people are going to sit it next to the router?

Or is it really just a very nice Wi-Fi/Bluetooth receiver?

IMO, I believe a dedicated streamer offers significant benefits vs. phone based streaming.
1. Allows streaming process to occur without requiring a phone. This allows phone use for other purposes without any effect on music streaming.
2. Allows potentially better stream quality then some phone based solutions, i.e. Spotify Connect on a streamer providing lossless CD stream vs. Spotify phone app using Airplay or BT lossy stream.
I very much appreciate the benefits of a dedicated streaming device that provides music playback without use of a phone. Also in our Apple ecosystem home, it allows letting Siri to support verbal requests for music management. I expect to the same benefits would apply for Amazon or Google based homes.
For me the WiiM products we use have been quite satisfactory and deliver very good performance. While I am intrigued by the S3 and its balanced outputs, the very good user experience we have with the WiiM systems we use is enough reason to be happy with what we have and enjoy the music. Cheers!

 

[Audionaut]

While I am intrigued by the S3 and its balanced outputs

I see this mentioned often, but from a purely technical standpoint, I don’t understand it. I think it’s a myth that you absolutely must have balanced wiring to achieve the best possible sound quality.

Balanced in-and outputs use two signal wires in opposite phases (hot and cold) plus ground. Interference typically couples equally to both conductors and is largely eliminated in the differential input through subtraction (common-mode rejection). The practical benefit therefore lies primarily in the suppression of hum and crosstalk, as well as in the ability to use very long cable runs with minimal interference.

In a typical home setup with short connections of about one meter using RCA (Cinch) cables, however, this advantage is usually hardly relevant. Amir’s Amazon Basic RCA cable set pretty much settles the issue of connectivity. With properly built equipment (which is, of course, a basic requirement) and reasonable cabling, interference rarely occurs to a degree that a balanced connection would audibly improve the sound. Accordingly, there are normally no sonic advantages over unbalanced connections, and there is no advantage over digital connections anyway, since the signal is not transmitted analogically there.

In practice, balanced connections are therefore truly useful and relevant primarily in studio and PA environments with long cable runs and complex setups, because interference is much more likely to occur there. In classic home audio applications, they are often more of a convenience or safety measure than a pure necessity, and in my opinion, their importance is completely overrated.

 

[TheLavenderBaron]

I see this mentioned often, but from a purely technical standpoint, I don’t understand it. I think it’s a myth that you absolutely must have balanced wiring to achieve the best possible sound quality.

Balanced in-and outputs use two signal wires in opposite phases (hot and cold) plus ground. Interference typically couples equally to both conductors and is largely eliminated in the differential input through subtraction (common-mode rejection). The practical benefit therefore lies primarily in the suppression of hum and crosstalk, as well as in the ability to use very long cable runs with minimal interference.

In a typical home setup with short connections of about one meter using RCA (Cinch) cables, however, this advantage is usually hardly relevant. Amir’s Amazon Basic RCA cable set pretty much settles the issue of connectivity. With properly built equipment (which is, of course, a basic requirement) and reasonable cabling, interference rarely occurs to a degree that a balanced connection would audibly improve the sound. Accordingly, there are normally no sonic advantages over unbalanced connections, and there is no advantage over digital connections anyway, since the signal is not transmitted analogically there.

In practice, balanced connections are therefore truly useful and relevant primarily in studio and PA environments with long cable runs and complex setups, because interference is much more likely to occur there. In classic home audio applications, they are often more of a convenience or safety measure than a pure necessity, and in my opinion, their importance is completely overrated.

I use Fosi Monos to add variety to my main system. SINAD for XLR is 100db vs 94db for RCA. A tangibile advantage and the main reason I got the S3, the other reason is that I just use Spotify for streaming and the S3 works great for that purpose.

 

[OrangeWalrus]

I see this mentioned often, but from a purely technical standpoint, I don’t understand it. I think it’s a myth that you absolutely must have balanced wiring to achieve the best possible sound quality.

Balanced in-and outputs use two signal wires in opposite phases (hot and cold) plus ground. Interference typically couples equally to both conductors and is largely eliminated in the differential input through subtraction (common-mode rejection). The practical benefit therefore lies primarily in the suppression of hum and crosstalk, as well as in the ability to use very long cable runs with minimal interference.

In a typical home setup with short connections of about one meter using RCA (Cinch) cables, however, this advantage is usually hardly relevant. Amir’s Amazon Basic RCA cable set pretty much settles the issue of connectivity. With properly built equipment (which is, of course, a basic requirement) and reasonable cabling, interference rarely occurs to a degree that a balanced connection would audibly improve the sound. Accordingly, there are normally no sonic advantages over unbalanced connections, and there is no advantage over digital connections anyway, since the signal is not transmitted analogically there.

In practice, balanced connections are therefore truly useful and relevant primarily in studio and PA environments with long cable runs and complex setups, because interference is much more likely to occur there. In classic home audio applications, they are often more of a convenience or safety measure than a pure necessity, and in my opinion, their importance is completely overrated.

I accept your rational explanation. XLR may be unnecessary, like SINAD over 90dB, but I like the assurance that I can run my signal cables alongside many miscellaneous cables in my tight cabinet and not worry about it. Also, cable cost is strangely similar while sticking to Amazon Basics or Monoprice quality.

I consider XLR a nice luxury for home audio use, and enjoy the hefty connectors with positive mechanical connections. It's less a rational decision and more an emotionally satisfying decision.