Cambridge Audio Azur 851D DAC

Description

The Cambridge Audio Azur 851D is a high-end digital-to-analog converter designed as part of Cambridge Audio’s flagship Azur 851 series. Built to serve as the digital hub of an audiophile system, the 851D combines advanced upsampling technology, dual-DAC architecture, and extensive connectivity to deliver exceptionally detailed and natural sound from a wide variety of digital sources. When released, the unit quickly became known for offering reference-level performance at a comparatively accessible price point.

At the heart of the 851D is a pair of Analog Devices AD1955 24-bit DAC chips operating in a dual-differential configuration. This design improves channel separation and reduces noise, helping the DAC extract more detail and dynamic range from digital recordings. The DAC stage is paired with a powerful 32-bit Analog Devices Black Fin DSP processor, which runs Cambridge Audio’s proprietary ATF2 (Adaptive Time Filtering) upsampling algorithm. This system converts all incoming digital signals to 24-bit/384kHz, dramatically reducing jitter and improving timing accuracy before the signal reaches the conversion stage.

The 851D also functions as a digital preamplifier, allowing it to connect directly to a power amplifier or active speakers without the need for a separate preamp. This flexibility makes it especially attractive for minimalist high-end systems. The unit includes balanced XLR and unbalanced RCA analog outputs, along with a high-quality headphone amplifier capable of driving headphones up to 600 ohms.

Connectivity is another major strength. The DAC features multiple digital inputs including USB, coaxial S/PDIF, optical Toslink, BNC, and AES/EBU, allowing users to connect everything from computers and CD transports to streamers and media players. The USB input supports asynchronous audio for high-resolution playback from a computer, while the included Bluetooth receiver enables convenient wireless streaming with aptX support.

Cambridge Audio also incorporated three selectable digital filter modes—linear phase, minimum phase, and steep—allowing listeners to tailor the sonic character of the DAC to their preferences or to different recordings.

Build quality is typical of Cambridge Audio’s premium components. The 851D features a rigid metal chassis designed to minimize vibration and electrical interference, along with a large toroidal transformer and carefully isolated circuitry for clean power delivery. These design choices contribute to the DAC’s reputation for precise imaging, wide soundstage, and exceptionally low distortion.

Review Highlights

Audio reviewers consistently praised the 851D for its performance and flexibility:

• “A superbly capable DAC with impressive connectivity and refinement.” — audio review commentary

• “The ATF2 upsampling system dramatically reduces jitter.” — HiFiReport review

• “A DAC and digital preamp that can anchor a high-end digital system.” — industry product overview

Many listeners also appreciate the ability to pair the DAC directly with power amplifiers such as the Azur 851W, creating a streamlined digital front-end with minimal signal degradation.

Overall, the Cambridge Audio Azur 851D remains a highly respected DAC among audiophiles. Its combination of advanced digital processing, excellent build quality, and wide connectivity makes it a versatile centerpiece for high-performance two-channel systems built around digital sources.

Key Specifications

• Product Type: Digital-to-Analog Converter / Digital Preamplifier

• DAC Architecture: Dual Analog Devices AD1955 24-bit DACs

• Upsampling: ATF2 Adaptive Time Filtering to 24-bit / 384kHz

• DSP Processor: Analog Devices Black Fin ADSP-BF532 32-bit DSP

• Selectable Digital Filters: Linear Phase, Minimum Phase, Steep

• USB Audio: Asynchronous USB Type-B, up to 24-bit / 192kHz

• Digital Inputs:

  • 2 × S/PDIF coaxial

  • 4 × Toslink optical

  • 1 × BNC

  • 1 × AES/EBU

  • 1 × USB Audio

  • Bluetooth (BT100 receiver with aptX)

• Analog Outputs: Balanced XLR and unbalanced RCA

• Headphone Output: 6.35mm (supports up to 600Ω headphones)

• Maximum Power Consumption: 40W

• Dimensions: 430 × 115 × 360 mm (16.9 × 4.5 × 14.7 in)

• Weight: 7.5 kg (16.5 lb)

• Finish Options: Black or silver