iFi

ZEN Stream

£399

What's not to like about this cute little bit of kit? iFi's new ZEN Stream is a small streamer designed to be partnered with any USB DAC – such as the company's own ZEN DAC V2, more of which later. It is uniquely flexible for its £399 price, allowing direct connection to services such as Spotify Connect, Qobuz and Tidal Connect (with decoding of MQA mastered material), UPnP, AirPlay, and Roon, via the matching app.

It is compatible with a wide range of audio formats up to 384kHz PCM and DSD256, and its open-source architecture means that more functionality is promised via future firmware updates. A series of coloured LEDs indicate the sampling rate and format in use, but lack of space precludes visual display of your album artwork. It's powered by an external plug-top 9V DC power supply, and there are dual USB sockets plus a S/PDIF coaxial RCA output. If partnered with a ZEN DAC V2, it powers the latter via its USB socket, and iFi supplies the correct USB cable.

The ZEN Stream is designed to work with any USB DAC, which is great because you don't have to commit to another DAC when you buy this streamer. For example, many people have their specific favourites that they've built their systems around and don't want to change them.

I also tried iFi's matching £299 ZEN DAC V2 (pictured directly above and below) running its latest firmware during this review. It's a compact 32-bit desktop design, built to partner USB sources, so there is no S/PIDF coaxial or optical TOSLINK optical input. Although usable as part of a hi-fi system, it's very much aimed at headphone users wanting a high-quality DAC/headphone amp at a keen price. Both 6.3mm unbalanced and 4.4mm balanced Pentaconn headphone sockets can be found on the front panel, plus a balanced 4.4mm line output round the back.

A standard set of unbalanced RCA audio outputs is fitted, with a switch to toggle between fixed and variable operation. The former seems to sound slightly better than the variable and is around 3dB louder too. There's a Power Match option for headphone users to optimise output for IEM and over-ear headphones, plus a TrueBass feature to boost the bass performance for a more even response between high and low frequencies. TrueBass only affects the headphone outputs.

I found a small but noticeable difference in sound quality between the high and low Power Match options, by the way. The higher gain option sounds sharper and more immediate. When I increased the volume level on the lower gain setting, it sounded smoother and less immediate. Headphone power output is claimed to be 280mW (unbalanced) or 380mW (balanced) into headphones with an impedance of 120 to 600 ohms. Even using some old low-efficiency AKG K340s, I could achieve fairly high volume levels with the volume around the 2 o'clock setting.

Both these iFi products run fairly cool. The streamer gets mildly warm to the touch after an hour or so, but the DAC doesn't, even when powering headphones at fairly high volume levels. There's no on/off switch, which suggests the items might be meant to be left powered-up. The ZEN DAC V2 is powered from 5V DC, obtained from a USB socket. A power socket is provided, but no external power supply unit is included.

Compared to iFi's original ZEN DAC, the latest V2 features an XMOS 16-core chip rather than an 8-core type; this boosts audio processing power and increases clock speed and memory, the company says. The V2 also has an updated crystal clock offering reduced jitter, it is claimed, plus MQA decoding. Build quality is impressive for the price. The all-metal construction of these units feels solid, and the buttons and controls have a smooth positive feel. The level of finish is good, and the tapered wing-like shape looks attractive and stylish. Top marks here!

THE LISTENING

My daily streamer is an Auralic Altair G2, which is many times the cost of iFi's ZEN Stream – but not many times as good. I found the Auralic sounded more subtly delineated, but the improvement in no way reflected the price difference, showing what fine value the iFi is. The Auralic's sonic superiority was quite noticeable when I first switched between the two, but as is so often the case with hi-fi, this seemed to grow less significant once I'd listened for half an hour or so. To my ears, the ZEN Stream punches way above its weight.

For example, playing a recent MQA title on TIDAL – an album called Bach; A Strange Beauty – with pianist Simone Dinnerstein – I was impressed by the sheer power and sonority of the recording when streamed through the iFi, which sounded impressively rich. It really was good. Solo piano tracks sounded lucid yet refined and natural. The concerto was marvellous to hear, with full-bodied, weighty strings that had a lovely richness and warmth. Only intending to sample a few minutes, I listened to the end, so involving was the result. On TIDAL, MQA titles generally sounded best. The Decca Solti recording of Wagner's opera Parsifal was wonderfully vibrant. Non-MQA titles sounded good but usually a tad flatter.

I then tried the Kubelik Mahler 7 on TIDAL MQA, and it sounded very good – albeit not quite as impressive as the ripped CD. The recording had a tad less depth and fractionally reduced dynamic contrast when streamed, though the results were still close. It's interesting that a 16-bit, 44.1kHz ripped CD can still stand its ground against hi-res formats, and that happens with pretty much every streamer I've heard, not just the ZEN Stream.

Bringing the ZEN DAC V2 into the proceedings, and of course, I found it to be no match for the onboard digital converter built into Auralic's Altair G2. As the latter is way more expensive, so this hardly came as a complete surprise. The Altair G2 offered greater refinement and effortlessness, as you would expect. Streaming Beethoven's Sonata for Violin and Piano Op 96 on ECM with Yuko Shiokawa and Andras Schiff, it had a smooth unforced naturalness that was highly beguiling. The ECM recording is beautifully open and unexaggerated yet detailed and clear. Still, with the iFi pairing, the balance between violin and piano was nicely managed, and both instruments were reproduced superbly. It wasn't that far behind; you could still listen to it, having heard the Auralic, all the same.

Trying a quick blast of Wrecking Ball by Miley Cyrus on headphones through the ZEN DAC V2 and its TrueBass option gave the sound a bit more weight and low-frequency power without sounding boomy or thick. If I were using headphones, I'd engage TrueBass all the time. Some users have complained that the volume control becomes unbalanced at very low settings. I found evidence of this – the left channel cuts out before the right with the control close to zero. But it's very slight and would only be an issue with very efficient headphones.

I usually partner my laptop with a 2014 Shanling H1.1 DAC, but – having been seduced by the choices offered with streaming – I'd largely neglected to listen to my ripped CDs over the last two or three years. Too much to listen to! But, using the laptop with the ZEN DAC V2, I was forcibly reminded how impressive properly ripped CDs could sound. I like to engage the acoustic equalisation option in iTunes, feeling this improves the reproduction of many recordings. The effect is subtle but beneficial.

THE VERDICT

IFi's little ZEN Stream streamer is a seriously impressive new streamer, offering great functionality and fine sound in a small package at a low price. Its genius is that it will work with any DAC with a USB connection, which is most these days. Yet it's also a very pretty picture together with iFi's own ZEN DAC V2, both visually and sonically. Together they give an engaging and entertaining sound with more detail than you'd expect, plus a lot of operational flexibility in terms of driving headphones. I became rather taken with both of them and reckon they're both something of a steal – whether you're looking to use them in your main system or as a desktop or office companion.

Visit iFi for more information