Cyrus 40 ST Streaming Transport

The Cyrus 40 ST is a network streaming transport from Cyrus's flagship 40 Series, designed to bring high-resolution audio from every major streaming platform and your own music library into a single, uncompromising source component. It outputs via analogue line level, with conversion handled by an ESS Sabre ES9039Q2M 32-bit DAC, and accepts digital inputs from external sources, making it the natural digital hub of a 40 Series system.

BluOS Streaming Platform

The 40 ST is built around BluOS, one of the most capable and widely supported streaming platforms available. BluOS gives you access to Tidal, Qobuz, Spotify, Amazon Music, and a wide range of other services, alongside your own locally stored files via UPnP or USB. The BluOS app is available on iOS and Android and provides a consistent, well-designed interface for managing playback, browsing libraries, and building playlists. Multi-room functionality is included — if you have other BluOS-enabled devices in the house, the 40 ST integrates with them natively.

ESS Sabre DAC and Analogue Output Stage

At the heart of the 40 ST is the ESS Sabre ES9039Q2M 32-bit DAC, supporting high-resolution audio up to 24-bit/192kHz. Cyrus have built a dedicated analogue output stage around this chip rather than relying on a reference board design, preserving the DAC's wide dynamic range and low noise floor through to the output. The result is a streaming source that competes seriously with dedicated disc-based playback — and the DAC underpinning it is more than capable of justifying that claim.

The 40 ST also accepts external digital sources via coaxial and optical inputs, so it can serve as a DAC for a television, games console, or any other digital device in the same room, bringing them all through the same high-quality conversion and output stage.

Network Connectivity

The 40 ST connects via Gigabit Ethernet or Wi-Fi 5 (802.11ac, 2.4/5GHz). A wired connection is recommended for critical listening — it eliminates the variability of wireless and ensures the lowest possible latency — but the Wi-Fi implementation is robust enough for everyday use in most homes.

Display and Controls

The 40 ST carries the full 40 Series fascia design: a 5-inch high-resolution TFT display, toughened glass front panel, and hidden-until-lit capacitive touch controls. The display provides clear visibility of the current source, streaming service, track information, and playback status. A full-function remote is included and integrates with the wider 40 Series range for unified system control.

The 40 PSU Upgrade

Like all 40 Series components, the 40 ST is designed to accept the optional Cyrus 40 PSU external power supply, which moves power conversion into a separate chassis. Removing the power supply from the main unit has a measurable effect on the analogue output stage's noise performance — a meaningful step for listeners who want to extract the maximum from what the ESS Sabre DAC is capable of.

Technical Specifications

Who Is It For?

The 40 ST is for the listener who wants a single, high-quality streaming source at the top of the Cyrus range — one that handles every major platform, accepts external digital sources, and outputs at a level that stands up alongside the best disc-based players. It suits someone building a complete Cyrus 40 Series system, or a listener whose existing setup has outgrown a built-in streaming module and needs a dedicated source component to match the quality of their amplification.

Buying from Martins Hi-Fi

Martin's Hi-Fi has been in Norwich since 1968. Elizabeth Gould runs the business today, and we stock only brands we have heard properly and stand behind. Dave and Chris know the Cyrus range in depth and can demonstrate the 40 ST in our Norwich showroom — including a direct comparison with disc-based sources if that is a question you want answered before committing. If you are building a full 40 Series system, we can help you plan it from the ground up.

Contact us at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martin's page. We are at 85–91 Ber Street, Norwich, NR1 3EY.