- Manufacturer & Model
- iFi Audio's ZEN Stream Wi-Fi Audio Transport
A true Wi-Fi audio transport, Connectivity includes Ethernet, wireless, USB, digital coax, and compatibility with ROON, Chormecast, Spotify Connect, and TIDAL Connect, small form factor, easy to set-up, easy to operate, great sound.
iFi Audio's ZEN Stream is a compact, affordable W-Fi audio transport. Offering owners access to a variety of digital sources, Internet Radio stations, and compatibility with ROON, Chromecast, Spotify Connect, and TIDAL Connect, it's a music fan's delight. Build quality is excellent and both set-up and operation are extremely user-friendly. Stream transfers Wi-Fi audio with crystal clear clarity.
Today, we're turning our attention to the newest member of iFi Audio's compact family of ZEN audio products: ZEN Stream. Stream is crafted to perform audiophile-grade Wi-Fi transport duties without crushing your wallet or, thanks to the company's commitments and practices, dragging the environment through the gutter. It does so by stripping away amplification and DAC duties, leaving its energies focused on receiving and passing digital audio using select components and an open-source architecture.
Priced at $399, Stream might cost more than other ZEN devices, but it fills a void in a sparsely populated category. So, let's explore ZEN Stream's capabilities and see how it fares when asked to handle Hi-Res audio duties in two different playback configurations.
A Wi-Fi Transport
The concept of Wi-Fi audio is hardly novel. Wi-Fi, after all, is embedded in nearly every modern AV receiver and isn't hard to find integrated with DAC and DAC/Amp products. But what if you want to add Wi-Fi streaming to an existing system or break free from a brand's closed streaming platform? In either scenario, you'll need some sort of standalone transport device.
One option is the Raspberry Pi which costs roughly a quarter of Stream's asking price. Raspberry Pi is an excellent option for enthusiasts that like to tinker, and it's open-source, so owners aren't locked into one streaming platform or another. It's not plug-and-play, though, limiting its utility to those with technical skills sharp enough to assemble and program a device. And its basic configuration isn't optimized for audio performance. That's what makes a product like ZEN Stream so intriguing.
ZEN Stream arrives preconfigured and ready to rock out of the box, giving owners access to an open-source, Linux-based architecture built with audio-grade components and design elements. It's a true Wi-Fi transport and ships with the promise of future community-inspired upgrades using over-the-air updates. It also has built-in conveniences you won't find with Raspberry Pi, including Spotify Connect and TIDAL Connect, Airplay, and Chromecast and ROON Ready functionality (the latter two will land with a future update). Toss in DLNA, compatibility with favorite streaming apps like J. River and Audirvana, and Network Audio Adapter functionality with the Sygnalist HQPlayer, and Stream has the tools to please a wide range of enthusiasts.
iFi's design team nailed the unified look of its entire ZEN lineup, and Stream is no exception. Weighing a smidge over 1-pound, Stream's thick aluminum shell and low sheen texture feel like magic in the hands, and its finer design elements lend to a visually pleasing package. Take, for example, its angled faceplate, which proudly wears "STREAM" etched in a shiny brushed metal surface. Or consider the rear plate's recessed connection points artfully framed by beveled edges. These and other appointments give Stream an extra bit of flavor and physical appeal.
Stream's faceplate is sparsely populated, devoid of a fancy display or clusters of switches and knobs. Instead, it carries a small symmetrical layout of buttons and lights. The two largest lights are color-changing and provide general information about the device's network connection and incoming sampling frequency (PCM 44.1/96kHz, PCM 176.4/384kHz, DSD 64/128, and DSD 256). The two smaller lights are associated with buttons that toggle Stream's power and hotspot status.
Moving around back, we find a Wi-Fi Antenna attachment point, an "exclusive mode" selector knob, a SPDIF/Coax output, two USB Type-A ports with USB 2.0 and 3.0 compatibility, Ethernet, and a DC power supply connection. There's also a system firmware upgrade port and a factory reset button.
Every button, light, and connectivity option – front and back – is marked by a small etched label. While iFi deserves a pat on the back for keeping it classy, a lack of contrast between Stream's silvery surfaces and these diminutive labels make words and symbols nearly impossible to read. I found my phone's flashlight (and reading glasses) made the etchings legible, but the inability to quickly recognize them is a bit of a miss.
ZEN Stream is designed around a 64-bit quad-core ARM Cortex microprocessor capable of supporting Hi-Res audio via LAN and Wi-Fi connections (802.11n with 100Mbps on 5Ghz). iFi says a range of audio-improving components are packed inside the chassis, headlined by surface mounted TDK C0G multilayer ceramic capacitors and inductors from Taiyo Yuden and Murata. Other notables include high Power Supply Rejection Ration (PSRR) low-idle current, low-dropout voltage regulators, and a synchronous 1.6MHz high-speed precision power supply controller. Toss in Active Noise Cancellation II, iPurifier technologies, and a Femto-Precision GMT clock across USB and S/PDIF interfaces, and Stream – according to the company – has the tools needed for ultra-clean performance.
Stream's exclusive modes shut down non-essential operations, allowing the transport to operate with the cleanest slate possible. It ships with an "all-in-one" mode engaged, which is a default setting for general operation. Other modes are intended for use with DLNA, Network Audio Adapter (NAA), ROON Ready, and TIDAL Connect playback. As for their utility, my ears couldn't discern a difference. Of course, a combination of your ears and your gear may produce different results.
Much like ZEN Blue (reviewed here), ZEN Stream ships in thoughtful, eye-catching packaging that sets the stage for a fun product reveal. So, if you're a fan of the unboxing experience, you'll find a lot to like about ZEN's efforts with Stream.
Inside the box, you'll find Stream, a Wi-Fi antenna, an external power supply, a plastic screwdriver to select exclusive modes, and basic set-up instructions. The bulk of set-up is performed with a phone or handheld device, using standard procedures to integrate Stream with a home network. If you have any experience setting up a network audio player or wireless speaker, you'll have no trouble getting Stream up and running. And for those who are electronics-shy, as long as you have some level of comfort with a phone or smart device, you should be fine. Based on my experience, most owners should budget 10 to 15 minutes for unboxing and set-up.
I tapped Stream's USB output to feed a THX Onyx DAC Amplifier driving a pair of OPPO PM-1 Planar Magnetic Headphones for the first half of this review. Later, the S/PDIF port was used to bring a StormAudio ISP 24 MK2 processor into the mix – audio was ultimately delivered by an Emotiva XPA-5 amp and GoldenEar Triton One.R tower speakers. Performance evaluations used a mixture of CD-quality files stored on a USB thumb drive and Plex on a Mac. Music was also sourced from Qobuz via Airplay and both Spotify Connect and TIDAL Connect.
ZEN Stream's playback prowess is legit, anchored by its ability to handle PCM up to 32-bit/384kHz and DSD up to 11.2MHz; heights of resolution that far exceed the insane audio purity we enjoy with routine 16/44 CD quality sound. When connected to my ISP 24 MK2 processor or THX Onyx DAC/Amp, Stream consistently delivered a clean signal devoid of crackles, dropouts, pops, or other distracting annoyances. Sound quality never deviated to problematic areas, providing a squeaky clean foundation for a full-range audio experience. I enjoyed nearly seven weeks of daily testing; music and podcasts always sounded exactly as expected.
Beyond serving as a gateway for reference playback, Stream's usability was impressive. As detailed, set-up was easy, and the amount of tech-savviness required to play audio never extended far beyond what most music fans need to operate Bluetooth on a smartphone. In other words, playing tunes was business as usual.
In the case of streaming services, Spotify Connect and TIDAL Connect (including MQA Master tracks) were passed without a hitch, and it was easy to enjoy AV NIRVANA's exclusive "Staff Picks" playlist on Qobuz. ROON access was also hassle-free, despite Stream's ROON Ready status still lingering in the pipeline.
Stream's web-browser interface (http://ifs.local/browse) and iFi's own Stream-Fi app (version 1.3, iOS) both connected to Stream in short order, opening access to basic settings, the ability to select an output device, and hundreds upon hundreds of internet radio stations. They also allow for the management of music from associated networked servers and USB drives. During testing, the browser interface immediately identified my Mac's Plex server on the local network and a USB stick inserted directly into the unit, making it easy to select and play albums and songs.
Playback volume levels were managed using the physical controls on my phone or by accessing a 20-point sliding volume control within the browser interface – both methods were responsive and practically lag-free. It's worth noting that Stream's default volume setting caps at 50% of max output. This means a device's physical controls can only increase Stream's output volume between 0 and 50 on a scale of 100. If you want more volume, you'll need to open the web browser and increase levels there (or change default settings). For purposes of this review, I set the default startup volume to 100, which gave physical controls the ability to increase output from 0 to 100.
Some confusion tripped up my experience using the browser and app, which was generally very positive. Despite appearing to provide control over streaming services such as TIDAL and Qobuz, neither do, which led to the appearance of buggy and unresponsive interfaces. Per iFi, playback control over these services should be left to their native apps, and volume control should only be executed using a device's physical volume controls. With that in mind, everything worked as billed. Hopefully, future iterations of these interfaces will make it clear when they can and cannot be used.
I also experienced a few glitchy app moments that iFi's engineers believe were caused by a network issue on my end. I didn't experience skips or dropouts during playback, which leads me to believe that Stream maintained a strong network connection. Nevertheless, some sort of misfire involving my device, network, and the app occurred every once and awhile; more than likely, some combination of my home network and iPhone was the root cause of the issue.
On a positive note, both control interfaces provided song resolution information (sampling frequency and bits) for songs played from my Plex server, USB drive, ROON, Qobuz, TIDAL Connect, and Spotify Connect. This is a welcomed feature, largely because Stream's front panel LED is only capable of relaying generalized information about a song's resolution (for example, a green light indicates sampling frequencies of 44.1, 48. 88.2, and 96kHz). While the LED provides a quick confirmation of the kind of audio that's incoming, it's nice to know owners can dig deeper if desired.
iFi Audio says gapless playback is possible with PCM streaming and a DAC capable of resolving it. So, I tested gapless using a 16-bit/44.1kHz copy of Pink Floyd's The Wall played from a USB stick and streamed through Plex. The result was seamless transitions between songs like "The Happiest Days of Our Lives" and "Another Brick in the Wall, Part 2" while feeding both the THX Onyx and my Storm ISP MK2 processor, confirming gapless performance. Just be forewarned: your mileage may vary depending on the kind of DAC you employ.
Finally, it's worth mentioning that Stream's physical controls and short boot-up process (from Off to On) were reliable, predictable, and fast. Also, the unit proved to be a source of minimal heat, remaining slightly – very slightly – warm to the touch.
Priced at $399, ZEN Stream is a solid way to bring Hi-Res Wi-Fi streaming to your favorite DAC or legacy stereo gear. Sized to fit anywhere – including a desktop – its handsome chassis delivered plug-and-play capabilities that kept my favorite tunes clean and intact.
Stream does so much right; it's hard to find many faults. Its biggest ding, in my opinion, is the lack of a digital optical output. Of course, S/PDIF is an easy substitute (assuming you have a proper coax cable is on hand), but the inclusion of an optical out would have been welcomed. Also, I'd like to see iFi make some improvements in the app department, making it clear when the app can and cannot be used for playback control.
Having spent more than a month streaming tunes from TIDAL, Qobuz, and Spotify, along with a vast sea of internet radio stations accessed through the browser interface, ZEN Stream passed every musical test with flying colors. Add solid support for playback from USB memory sticks and network servers, and iFi gives music fans lots of reliable and clean performance for the coin. Great gear – Recommended!
iFi Audio's ZEN Stream Wi-Fi Audio Transport Specifications
- Input voltage: DC 9V/1.8A-15V/0.8A; AC 100 -240V, 50/60Hz
- Input: Wi-Fi / Ethernet / USB HDD (Firmware updates via OTA and USB-C at rear)
- Formats: PCM384. DSD256, (MQA-fully compatible)
- Output: USB3.0 (Type-A Socket) x2, SPDIF (Coaxial)
- Power consumption: No Signal ~6W
- Max Signal: ~10W
- Dimensions: 158 x 100 x 35 mm (6.2" x 3.9" x 1.4")
- Net weight: 578g (1.14 lbs)