LHY RPI Pro

LHY Audio RPi Pro

High-performance streamer and digital bridge

El LHY Audio RPi Pro It is a streamer and digital transport developed to integrate the flexibility of the Raspberry Pi platform into a component built specifically for high-end audio systems.

Inside it incorporates a Raspberry Pi Compute Module 4, accompanied by a board designed by LHY Audio, dedicated low-noise power supply, USB isolation, optical network connection and an advanced clock system. Its function is to receive the music via the network and deliver the digital signal to the DAC with the highest possible stability and the lowest electrical noise.

Unlike a conventional Raspberry Pi, the RPi Pro integrates a complete audio-oriented architecture: 30 VA Talema toroidal transformer, EMI filtering, high-speed rectification and three independent power supply lines for the various digital circuits.

A flexible digital transport

The RPi Pro can be used as a playback endpoint for Roon, as a network adapter for HQPlayer NAA or as a streamer compatible with UPnP, DLNA, AirPlay, Spotify Connect, Tidal Connect and Squeezelite, depending on the installed operating system.

Arrives with Pre-installed RoPieee, facilitating its integration into Roon systems. It can also be used with Volumio, Moode or PiCorePlayer. The operating system is stored on a microSD card, making it possible to change platform simply by replacing the card.

It does not incorporate a DAC: its mission is to transport the digital signal from the network to an external converter.

Ethernet network and fibre optic isolation

Connection available Gigabit Ethernet RJ45 and from a port 1.25 Gbps SFP, compatible with optical or copper modules.

The fibre-optic connection makes it possible to interrupt the electrical continuity between the home network and the hi-fi system. This helps to prevent some of the noise originating from the router, switch, computers and connected devices from reaching the streamer and the DAC.

RJ45 and SFP connections function as network interfaces, although they should not be connected simultaneously to the same local network.

Native and isolated USB output

The USB 2.0 output comes directly from the Compute Module 4 processor, with no intermediate PCIe conversions. The signal then passes through a digital isolator Analog Devices ADuM3165, powered by a separate line.

This configuration helps to reduce the transmission of electrical noise to the DAC and supports high-resolution signals of up to PCM 768 kHz/32-bit and native DSD512.

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High-precision OCXO clock

The RPi Pro incorporates an oscillator Ultra-low phase noise SC-cut OCXO, with a typical value of –100 dBc at 1 Hz. This oscillator provides the reference to the Skyworks Si5381 PLL, which is responsible for generating and synchronising the clocks required for the processor, the network and the USB interface.

It also includes a BNC input for connecting a external 10 MHz 50 ohm master clock. When it detects a compatible external reference, the system automatically performs the switchover.

I²S digital output

The I²S output allows the RPi Pro to be connected directly to certain compatible converters, supporting up to 768 kHz/32-bit PCM and DSD128 via DoP.

This output does not provide an MCLK signal. Therefore, its compatibility depends on the design of the DAC. It works correctly with converters capable of recovering or internally generating their master clock, but might not be compatible with DACs that need to receive an external MCLK signal.

Construction and earthworks

The entire assembly is housed in a robust machined aluminium chassis, which provides mechanical stability and protection against interference.

The rear panel includes a switch Ground Lift to connect or disconnect the earth coming from the power input, as well as a terminal intended for an independent external earth connection. These settings make it possible to adapt the earthing to the behaviour of each system.

Technical specifications

Processing and storage

• Platform: Raspberry Pi Compute Module 4
• Available RAM memory: 4 GB or 8 GB
• System storage: high-speed microSD card
• Included capacity: 64 GB
• Pre-installed system: RoPieee
• Compatible systems: Volumio, Moode and PiCorePlayer
• System change: by replacing the microSD card

Streaming services and protocols

• Roon via RoPieee
• HQPlayer NAA
• UPnP
• DLNA
• Spotify Connect
• Tidal Connect
• AirPlay
• Squeezelite

The specific availability of each service depends on the installed operating system.

Clock system

• Internal oscillator: SC-Cut OCXO
• Typical phase noise: –100 dBc at 1 Hz
• Frequency stability: ±0.3 ppb
• Frequency accuracy: ±1 ppm
• PLL: Skyworks Si5381
• External clock input: 1 × BNC
• Reference frequency: 10 MHz
• Impedance: 50 Ω
• Input level: 7–14 dBm or 0.5–1 V RMS
• Selection of the external clock: automatic

USB audio output

• Connector: USB 2.0 Type-A
• Signal origin: native output from the CM4
• Isolation: Analog Devices ADuM3165
• PCM resolution: 44.1–768 kHz/32-bit
• DSD: Native DSD64, DSD128, DSD256 and DSD512

I²S output

• PCM: 44.1–768 kHz/32 bits
• DSD: DSD64 and DSD128 via DoP
• MCLK signal: not available
• Compatibility: depends on the DAC's I²S architecture

Network connections

• Ethernet RJ45: 10/100/1000 Mbps with auto-negotiation
• SFP port: 1.25 Gbps
• Supported speeds via SFP: 10/100/1000 Mbps
• Compatible SFP modules: optical or copper
• Network isolation: via SFP optical connection
• Jumbo frames: supported by the hardware; availability depends on the operating system and network configuration

Other connections

• HDMI output for system monitoring
• MicroSD card slot
• Ground lift switch
• External earth terminal
• IEC power inlet
• Accessible fuse holder

Food

• Talema 30 VA toroidal transformer
• Input filtering: multi-stage EMI
• Grinding: high speed
• Internal power supply: three independent low-noise rails
• Tensión para Europa: 220–240 V AC
• Consumo en espera: 8 W
• Consumo durante el funcionamiento: 12 W
• Fusible para 220–240 V: 5 × 20 mm, T1.0AL
• Fusible para 110–120 V: 5 × 20 mm, T2.0AL

Construction

• Chasis: aluminio macizo mecanizado
• Dimensiones: 275 × 240 × 50 mm
• Peso: 5,5 kg
• Available finishes: black and silver

Included accessories

• Tarjeta microSD de 64 GB
• Mains cable
• Cable Ethernet Cat 6
• Guantes de manipulación

Nota: el LHY Audio RPi Pro es un transporte digital y no incorpora conversión digital-analógica. Para obtener señal de audio analógica debe conectarse a un DAC externo compatible.