Streamers — Cyrus Audio 40 ST

The 40 ST is the network player of the Cyrus 40 series, a half-width family designed and built in the UK that also contains the 40 AMP integrated amplifier, the 40 CD player and an optional 40 PSU outboard supply. Streaming runs on the BluOS platform, and the circuitry sits inside the precision-milled aluminium casework that gives the 40 range its shared appearance. Cyrus positions it as a source that can later be upgraded with the external supply rather than replaced.

Key specs that matter

Digital to analogue conversion uses an ESS Sabre ES9039Q2M 32-bit chip in the HyperStream IV Dual DAC topology. Cyrus lists PCM playback up to 24-bit/192kHz from the network together with DSD256, plus MQA decoding. The chip itself is specified by ESS for 32-bit/768kHz PCM and DSD1024, so the streaming ceiling comes from the platform, not the converter. Two pairs of RCA line outputs carry the analogue signal, and a coaxial and an optical socket give a digital output. Digital inputs on the back, again one coaxial and one optical, mean a TV or a disc transport can use the internal converter, while a USB-A socket handles local files stored on a stick or drive. Networking is via Gigabit Ethernet on RJ45 or dual-band Wi-Fi 5 (802.11ac, 2.4 and 5GHz). The case is 88 mm high, 220 mm wide and 385 mm deep, and the unit weighs 4.8 kg. There is no Bluetooth receiver.

Engineering and use context

BluOS gives native access to more than 20 streaming services and internet radio, and it reads a library stored on a network drive. The BluOS controller runs on Apple and Android phones, Kindle tablets and Mac or Windows computers, and firmware arrives over the network. The player is Roon Ready and accepts AirPlay 2, which also allows Siri voice commands from Apple devices. A 15-pin socket on the back accepts the 40 PSU, which takes over the supply with digitally managed power so the player can be upgraded in stages. Cyrus describes the build as handcrafted in Britain, and the half-width footprint lets the player and a matching amplifier stand side by side on one shelf.

Pairing

The natural partner is the 40 AMP from the same series, which shares the chassis width and styling, and the two RCA output pairs let a second analogue device receive signal in parallel. Anyone who already owns an outboard DAC can take the S/PDIF feed from the digital outputs and use the 40 ST only as a network transport. The digital inputs let a television optical feed or a CD transport pass through the ESS converter without extra boxes.

Alternatives

Cyrus also offers the Stream-XR, a streamer housed in the darker Phantom black XR casework with an ES9038Q2M converter and a socket for the optional PSU-XR outboard supply.