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Product name: Fosi Audio Q6
Manufacturer: Fosi Audio - China
Cost: approx 90€
Reviewer: Piero Canova - TNT-Audio Italy
Reviewed: May, 2025

Foreword

I believe that no Hi-Fi enthusiast has not realized the revolution that is taking place with the expansion of music without physical support or, if you prefer, liquid. Data connections are now so high-performance that you can obtain both high-quality files in very short times and at reasonable costs for those seeking audio perfection, as well as digitalized historical finds that would have been unattainable without this distribution system. If obtaining files has therefore become easy and convenient, we now have to transform them into analog signals to be able to listen to them, a component is becoming critical and cornerstone of many systems: the Digital-Analog Converter (DAC).

DACs have always existed but they were either professional machines or special components for very demanding audiophiles. They were usually limited to converting CDs and therefore able to manage a sampling frequency of 44,1 KHz and 16 bit.

Today DACs have become real data processing centres based on very sophisticated processors and have progressively absorbed secondary functions such as headphone amplification, volume control and wireless connectivity via Wi-Fi or Bluetooth. To make a long story short, today it is possible to build a top-level system with a computer, a suitable DAC and a power amplifier. Two power cables and an interconnect cable: think of the money saved on these components alone. At TNT-Audio we are always looking for new components with an excellent quality/price ratio and therefore we could not miss the new DAC from Fosi Audio, the Q6.

How it's made

The external appearance of the Q6 is perfectly in line with the other Fosi Audio products already reviewed. A small matt black box, on the front a toggle switch for the power and the usual round knob to choose the input. On the back are the connectors for the three inputs: an RCA for the coaxial input, one for the optical input and a USB C for the USB connection. The outputs are a pair of RCA for the analog signal and an additional RCA connector for a sub-woofer. There is no power socket in the sense that the DAC is powered by the USB socket. If you want to use it as a DAC downstream of a CD transport like I did, look for a phone charger because otherwise it won't work. I confess that I raised at least an eyebrow at this choice because the digital part probably has negligible consumption but downstream there is an amplification section that we will have to power adequately. For the uninitiated, I'll try to simplify the whole thing by saying that a high-performance DAC is made up of a somewhat split power supply where one part powers the digital section and the display while the second powers the analog and amplification part. Here everything is mixed up and the task falls on a Samsung quick charge phone charger.

The conversion is done by a single AKM 4493 SEQ processor which is a great processor found in much higher level DACs. It is a stereo processor characterized by low distortion and a very extended dynamic range. It would also have 6 digital filters on board but evidently to reduce costs it is not possible to access this function. In short, the engine is not bad at all. The amplification is based on operational amplifiers: one OPA1612 and two NE5532. As you can see from the internal photo, the components are very few but this is common on digital designs so there is every hope of a good performance.

How does it sound?

Setup is a breeze: a coaxial cable from the CD player to the Q6, the phone charger with a USB cable to power it, and two RCA cables to connect it to the preamp. You turn it on with the toggle switch on the front, choose the connected input, and you're ready to listen. Compared to its fellow countryman Topping D90 SE that I currently use as a DAC, the dimensions are similar. There's no display and the flexibility in terms of inputs and settings is much less, but the price is also a tenth so it's understandable and acceptable that a series of secondary functions are missing.

As always, I let new devices run in for a few hours before starting to listen. After a couple of days I think we are ready for serious listening and I look for some well-recorded CDs to immediately evaluate their performance. From the beginning I realize that something is wrong. It's not that something is missing or that some part of the audio spectrum sounds bad; it's the whole that is not convincing. Bass, mids and highs are there, the soundstage is wide and deep enough, the instruments are all there so what's wrong? The presentation is flat, without dynamics and the instruments lack body. The voices are unnatural and without feeling. It's like a text written by AI: everything is correct, nothing out of place but the result is totally anonymous. I thought that the culprit was the power supply and so I looked for a nicer one made in Cupertino but no improvement. I tried to change the source using the USB input from the computer but the result remained the same. My feeling is that the analog stage does not do justice to the performance of the DAC because there are good sounding machines that use the same chip but here we are in the realm of hypotheses. I tried to bring it back to its chosen territory, that is, to use it as an external DAC for a computer station and things are definitely better but here the requests and expectations are much lower. The comparison with the Topping D90SE is simply merciless for the Q6; all the attempts I made to improve its performance were useless because the benefits obtained were truly marginal.

Conclusions

On the Fosi Audio website, the manufacturer correctly says that it has used audiophile quality components and a chip but never says that its DAC is intended for audiophile use and indeed, if you evaluate it as an external DAC for a computer we are faced with an excellent machine and it is worth the asking price. However, the P4 pre-amplifier tested a month ago had performed well above its price and can also be used in high-level systems and this had generated higher expectations. I believe that, if the project were revisited and improved in the analog stage, a very interesting machine could be obtained. Even a slightly better external power supply could improve performance. In the end, I do not feel like recommending it as a DAC in a Hi-Fi system even if it were entry level ; for a little more money you can find much better and seriously good sounding machines.

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© Copyright 2025 Piero Canova - piero@tnt-audio.com - www.tnt-audio.com

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