Cyrus 40 ST Streaming Transport

The Cyrus 40 ST is a network streaming transport from the flagship 40 Series — a dedicated source component designed to bring high-resolution audio from every major streaming platform and your own music library into a system of uncompromising quality. Built around the BluOS streaming platform and a custom-implemented ESS Sabre 32-bit DAC, the 40 ST is the natural digital hub of a complete 40 Series system, and a formidable streaming source in any high-performance context.

BluOS Streaming Platform

The 40 ST is built around BluOS — one of the most capable, stable and widely supported streaming operating systems in consumer audio. BluOS gives access to Tidal, Qobuz, Spotify, Amazon Music, and a wide range of other services, alongside 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 other BluOS-enabled devices exist elsewhere in the house, the 40 ST integrates with them natively, without additional configuration.

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 chipset rather than deploying it in a reference board configuration — a decision that preserves the DAC's wide dynamic range and low noise floor through to the output. The 40 ST also accepts external digital sources via coaxial and optical inputs, allowing it to serve as the DAC for a television, games console or any other digital device in the same room.

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 — eliminating the variability of wireless and ensuring 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: 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 at all times. 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 accepts the optional Cyrus 40 PSU external power supply. Moving power conversion into a separate chassis 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, dedicated 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 comparison with the best disc-based players. It suits those building a complete 40 Series system and pairs naturally with the Cyrus 40 CD for a complete digital source pairing. Those who want to go further should consider adding the Cyrus 40 PSU as a first upgrade.

Buying from Martins Hi-Fi

Martins 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 [email protected], call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins Hi-Fi page. We are at 85–91 Ber Street, Norwich, NR1 3EY.