Overview

The iFi Audio ZEN Stream is a dedicated network audio transport priced at 399 USD. It bridges streaming services and local network sources to an external DAC via two USB 3.0 (Type-A) ports and a coaxial S/PDIF output. It supports up to PCM 32-bit/384 kHz and DSD256 over both Wi-Fi and Ethernet. Protocol support includes Roon Ready, Spotify Connect, TIDAL Connect, AirPlay, DLNA/UPnP, and an NAA (HQPlayer) mode [2].

Scientific Validity

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Independent measurements show the ZEN Stream performs excellently as a digital transport. GoldenSound reported “absolutely fantastic performance,” noting audible-band jitter artifacts below audibility and a noise floor around −107 dB relative to 4 V (20 Hz–20 kHz) on an APx555 analyzer [1]. As a transport, conventional THD+N/FR metrics on analog outputs do not apply; the relevant points are bit-perfect output and low interface-related jitter, both of which are satisfied here [1][2].

Technology Level

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The platform combines a quad-core ARM processor with a Linux/Volumio-based, open-source-derived stack, plus iFi’s GMT femto-clock, Active Noise Cancellation (ANC) on USB power, iPurifier on S/PDIF, and “Exclusive” modes that disable unused services to reduce software load [2]. These are solid, incremental engineering choices typical of modern streamers rather than breakthroughs.

Cost-Performance

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Selecting the cheapest equivalent-or-better finished product as the comparator yields the WiiM Ultra at 329 USD (market price) [3][4]. It provides USB audio out (up to 24-bit/192 kHz), coax/optical S/PDIF outs, and broad streaming support (e.g., Spotify/TIDAL Connect, Google Cast, Roon playback) [3][4].
Equivalence note: For the core “digital transport to external DAC” use case, WiiM Ultra matches or exceeds user-visible functions (USB/S/PDIF digital outs, bit-perfect hi-res streaming, app ecosystem). It lacks AirPlay while offering Google Cast instead; ZEN Stream supports AirPlay [2][4]. Given the audible-band transparency of both devices as transports and parity on principal outputs, we treat them as equivalent for CP.
Calculation: 329 USD ÷ 399 USD = 0.8.

Reliability & Support

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iFi lists a standard 12-month limited warranty (regional law may extend this) and supports OTA firmware updates [2][5]. While many units run stably, there are user reports of intermittent network dropouts on some systems, suggesting environment-dependent reliability factors [6]. Hardware is solid-state with no moving parts.

Rationality of Design Philosophy

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The design prioritizes transparent, low-jitter digital transport and practical protocol coverage over subjective processing. Offering USB and S/PDIF maximizes DAC compatibility, and “Exclusive” modes sensibly reduce software noise. The approach is rational and user-focused [1][2].

Advice

Choose ZEN Stream if you need a USB/Coax digital transport with AirPlay plus Roon/TIDAL/Spotify Connect in a tidy, purpose-built box. If Google Cast suffices (and AirPlay is not essential), the WiiM Ultra achieves equivalent transport goals for less money while adding a screen and integrated DAC/preamp functions [3][4]. DIY paths (e.g., Raspberry Pi 4) can be cost-effective for experienced users but are not a CP basis here; treat them as alternatives requiring more setup [7].

References

1. GoldenSound, “iFi Zen Stream Measurements and intro to streamers,” https://goldensound.audio/2021/07/22/ifi-zen-stream-measurements/ (2021-07-22), APx555 B-Series measurement set.
2. iFi Audio, “ZEN Stream: Wi-Fi Hi-Res Audio Casting for Your Hi-Fi,” https://ifi-audio.com/products/zen-stream/ (accessed 2025-08-26).
3. ABT, “WiiM Ultra Hi-Res Audio Streamer…,” price/specs incl. USB digital OUT up to 24/192, 329 USD, https://www.abt.com/WiiM-Ultra-Hi-Res-Audio-Streamer-in-Silver-ASR004S/p/211487.html (accessed 2025-08-26).
4. Crutchfield, “WiiM Ultra…,” indicates Google Cast, no AirPlay, Roon player support, price 329 USD, https://www.crutchfield.com/p_399WMULTRA/WiiM-Ultra-Space-Gray.html (accessed 2025-08-26).
5. iFi Audio, “Warranty,” https://ifi-audio.com/warranty/ (accessed 2025-08-26).
6. Audiogon Forum, “Problems with the IFI Zen Stream…,” user reports of network dropouts, https://forum.audiogon.com/discussions/problems-with-the-ifi-zen-stream-what-s-a-better-alternative (accessed 2025-08-26).
7. Twittering Machines, “Review: Raspberry Pi 4: A 70 USD Roon Ready Streamer,” https://twitteringmachines.com/review-raspberry-pi-4-a-70-roon-ready-streamer/ (accessed 2025-08-26).

(2025.8.27)