Fosi Audio ZD3 Review

Design

• 38mm OLED display
• Familiar black-with-orange-accents finish

Like many Fosi Audio products, the ZD3 is of entirely desktop-friendly dimensions. In fact, it’s built in the same 50 x 149 x 159mm (HWD) chassis as the company’s ZA3 stereo amplifier, and as a just-add-speakers pairing you’d find yourself in possession of an extremely tidy, extremely capable desktop audio system.

The Bluetooth aerial is no larger than is the norm, but when attached to a device this compact it looks disproportionately long.

The great standard of build and finish is predictable, as is the single black-with-orange-bits option for finish. The circular OLED display is necessarily small at 38mm, which can make reading some of the areas a bit of a trial – but it’s crisp and clear, and once you’re close enough it delivers a lot of relevant information. The orange control dial is the same size, and it deals with power on/off, input selection and volume.

Fosi Audio supplies a fully featured remote control handset in case your ZD3 is more than an arm’s-length away. It feels in no way special, but its buttons are all sensibly sized and the layout is logical enough.

Features

• ESS 9039Q2M DAC
• Physical and wireless inputs
• Replaceable DIP8 dual discrete op-amps

You’ve got to hand it to Fosi Audio – it knows how to put full-size specification into a compact enclosure. With the possible exception of headphone amplification, the ZD3 isn’t lacking anything you’d expect to find in a larger, more expensive stereo DAC/preamp.

There are four physical inputs here, plus Bluetooth 5 wireless connectivity with aptX HD codec compatibility. Between digital coaxial, digital optical, HDMI eARC and USB-B, the ZD3 is ready to support a system far larger than your average desktop.

Getting analogue audio information out can be done either via stereo RCA connections or balanced XLR alternatives – so compatibility with everything from powered desktop speakers to high-end power amplifiers is assured. But, of course, before you reach that stage the digital audio information needs to be converted.

The ZD3 is fitted with a very acceptable ESS 9039Q2M DAC that’s capable of handling 32-bit/768kHz PCM and DSD512 information if it comes via the USB-B socket.

The optical and coaxial inputs are good for 24-bit/192kHz PCM and even the Bluetooth input can work with 24-bit/48kHz stuff – Bluetooth inputs are handled by Qualcomm’s QCC3031 chipset before the ESS DAC gets involved. All of which should, I’m sure we can agree, be ample. 

What else? Well, the Fosi Audio’s DIP8 op-amps can be replaced by the end user with quite a variety of alternatives (including the well-regarded Sparkos SS3302 and Muse02 models) if the end user so desires. There’s a bypass switch on the base of the chassis – switch it on and the ZD3 becomes a pure DAC, with all its preamp circuitry omitted from the processing.

And there’s a trigger loop input/output on the rear of the chassis, allowing for synchronised power on/off across a system. 

Performance

• Balanced and organised sound
• Spacious, detailed presentation
• Could conceivably sound more assertive

It would not surprise me in the slightest if you own some digital audio equipment that doesn’t feature digital-to-analogue conversion as effective as that in this Fosi Audio. If you own a TV or a laptop that has D-to-A abilities that are anywhere near that of the ZD3, I’d be staggered.

So routing your digital sources through this little device is, in almost every respect, a good idea. In the course of this test I listen to a CD of Fusa Riot by The Bobby Hughes Experience through a vintage Rega Apollo CD player, a 24-bit/96kHz FLAC file of When We All Fall Asleep, Where Do We Go? by Billie Eilish stored on an Apple laptop, a 16-bit/44.1kHz TIDAL-derived stream of Mos Def’s Black on Both Sides via an iPhone, and an Amazon Video presentation of Distant Sky by Nick Cave & The Bad Seeds using a Philips OLED TV – and every time, the Fosi Audio makes its presence felt.

What the ZD3 does particularly well is offer a nicely balanced, properly controlled presentation. Its tonal response is clean and uncoloured, and it gives every area of the frequency range a very, very similar amount of weighting.

The soundstage it creates is large and well-defined, and the DAC is adept at placing just as much importance on the spaces and silences there as it does the actual occurrences. Every participant gets the below-room in which to express themselves, but they are confidently integrated into the overall performance – so there’s a very pleasing sense of unity to the way music is presented.  

Low frequencies are deep and textured, and controlled to the point that rhythmic expression is naturalistic and convincing. The top of the frequency range is about as shiny as it dares to be – but as long as your partnering electronics and speakers aren’t too treble-happy then the amount of bite and crunch the Fosi Audio summons will be pleasing rather than painful.

In between, the midrange is projected with real directness, and voices of all types are communicative as a result. And at every point, the ZD3 reveals plenty of the final detail that goes such a long way towards making for a full and eloquent account of a recording.

It’s only when it comes to outright dynamism and a sense of forwardness that the ZD3 is found lacking. Put simply, it’s just all that willing to, or capable of, really letting loose when a recording ramps up the attack, the intensity or the straightforward volume.

It’s a rather considered, almost polite performer that quite obviously values good taste over any vulgar displays of meaningful dynamic fluctuation. If you listen to music that requires proper drive and momentum, or that indulges in big dynamic shifts, you may find the Fosi Audio ZD3 just a little inhibited in this respect.

Should you buy it?