Skip Navigation

Cambridge Audio 851D

Stereo DAC/headphone amplifier/digital preamp (Black)

2 Reviews

Watch a first-look video

Item # 779851DB

This item is no longer available.

Shop all DACs


Our take on the Cambridge Audio 851D

When was the last time an audio component transformed the sound of your system? Here's one that can. Simply feed your digital audio sources into the Azur 851D and discover just how exciting they can sound. Cambridge Audio's exceptional flagship DAC will deliver your music with greater realism, detail, and dynamic impact than you may have thought possible. Plus, this multi-talented digital-to-analog converter acts a versatile digital preamp with enough inputs to handle a wide range of digital music sources: computers, disc players, game consoles, network music players, and more. It even includes a dedicated headphone amp for private listening and Bluetooth® wireless connectivity for high-quality wireless playback from your compatible portable devices.

More realism for your music

When was the last time an audio component transformed the sound of your system? Here's one that can. Simply feed your digital audio sources into the Azur 851D and discover just how exciting they can sound. Cambridge Audio's exceptional flagship DAC will deliver your music with greater realism, detail, and dynamic impact than you may have thought possible. Plus, this multi-talented digital-to-analog converter acts a versatile digital preamp with enough inputs to handle a wide range of digital music sources: computers, disc players, game consoles, network music players, and more. It even includes a dedicated headphone amp for private listening and Bluetooth® wireless connectivity for high-quality wireless playback from your compatible portable devices.

Built to exacting audiophile standards

The Azur 851D comes packed with advanced circuitry designed to extract the best possible sound from all your digital sources. Twin Analog Devices DACs are used in a dual differential configuration to cancel out noise and distortion while providing excellent stereo imaging. Cambridge's sophisticated Adapted Time Filter 2 technology upsamples all incoming digital audio to a 24-bit/384kHz signal to resolve extremely fine detail. The end result is dramatically improved sound from every digital source in your system.

Cambridge also included some neat features guaranteed to appeal to audiophiles. A choice of digital filter settings lets you tweak and fine-tune the DAC's sound to match your system and room. A phase inversion switch lets you correct for out-of-phase recordings or amplifiers that invert phase. And an incoming sample rate indicator verifies the original source quality. Behind it all stands a fully shielded toroidal transformer anchored to an acoustically damped, all-metal chassis for gobs of steady, quiet current and a vanishingly low noise floor.

All the right connections for your digital audio gear...

Back view silver

The Azur 851D offers versatile digital inputs for all of your sound sources plus RCA and pro-quality XLR audio outputs.

The 851D offers plenty of connections for your digital audio sources. You get  two digital inputs with your choice of optical or coaxial connections, ideal for plugging in a CD/DVD player, or a Sonos® Connect player. Plus there are two additional optical inputs just right for your HDTV, Apple TV®, or game console. Along with these common inputs there's a professional-grade BNC coaxial input and a balanced digital XLR input that provides an ultra-low-noise connection when used with a compatible high-end CD transport.  

High-res audio

...and your computer

A low-jitter, asynchronous USB port makes it easy to feed the digital audio from your computer into the 851D's high-end processor. This bypasses your computer's sound card to give you superior sound with stored or streamed music files. This DAC also decodes high-resolution music files with sample rates up to 192kHz, so you can enjoy better-than-CD audio quality. (Free USB driver download required for Windows® PCs.) If you download high-res music files from HDtracks and other audiophile sources, this DAC will ensure that you hear them in all their glory.

Cambridge Audio BT100 Bluetooth receiver

Stream music wirelessly from your Bluetooth-enabled audio devices to the 851D using the included BT100 receiver.

High-quality sound from an included wireless audio receiver

You can also go cable-free with Cambridge Audio's included plug-and-play BT100 Bluetooth® wireless audio receiver. This receiver lets you stream music wirelessly from your iPhone®, Android™ smartphone, iPad®, tablet, laptop or any device that supports Bluetooth audio. Best of all, if your smartphone, tablet, or computer supports high-end CSR aptX® Bluetooth audio, you can stream near CD-quality music from your device to this DAC.

It's a versatile digital preamp, too

The 851D is a fully functional digital preamplifier with a volume control. Unlike many digital preamps that use bit reduction to adjust volume — a process that results in degradation of the original digital audio signal — this DAC uses a powerful 32-bit Blackfin digital signal processor to control volume without reducing resolution. That means the entire digital signal remains intact to provide the best possible sound.

I have the dac Magic also,there is a difference in sound. The dac Magic plus is louder but seems to raise the treble and the 8151d has a more leveled detail in the sound quality. I bought this one because I needed more inputs

Mark, Cedar Rapids, IA

Featured Video:

What's in the Box:

  • Digital-to-analog converter
  • 6' AC power cord
  • IR remote control (RC-8/SM)
  • 3 "AAA" batteries
  • Bluetooth receiver (BT100)
  • 38" Mono-RCA cable
  • User Manual (En/Fr/Sp)
  • Quick Start Guide (En/Fr/Sp)

Product Highlights:

  • twin Analog Devices AD1955 24-bit digital-to-analog converters in dual differential mode for precise stereo imaging
  • asynchronous USB technology for reduced timing jitter and better sound from the USB input
  • Anagram Technologies Adapted Time Filtering 2 (ATF2) 24-bit/384kHz audio up-sampling with jitter reduction for resolving fine detail
  • preamp function with selectable inputs and remote volume control
  • built-in headphone amplifier and full-size (1/4") front-panel headphone jack (compatible with 12-600 ohm headphones)
  • Bluetooth wireless playback from compatible Bluetooth devices using the included Cambridge Audio BT100 wireless audio receiver
  • supports the high-quality Bluetooth aptX CODEC for streaming audiophile quality music from a compatible Bluetooth device
  • audiophile-grade toroidal transformer for ultra-low noise and distortion
  • phase-inversion (polarity) switch to compensate for out-of-phase recordings or phase-inverting amplifiers
  • remote control
  • two S/PDIF digital audio inputs: with one optical (Toslink) and one RCA coaxial each
  • two additional optical digital (Toslink) inputs
  • USB (Type B) for connecting a computer
  • one BNC coaxial digital audio input
  • one AES/EBU (XLR) balanced digital audio input
  • Bluetooth adapter
  • optical and coaxial digital outputs (pass-through)
  • stereo RCA output
  • stereo balanced XLR output
Other info & specs:
  • supported sample rates: 32kHz to 192kHz (USB, AES/EBU, coaxial, optical, BNC)
  • dedicated Cambridge Audio USB 2.0 driver required for 176.4kHz and 192kHz playback on a Windows® PC (free USB driver download available from Cambridge Audio website)
  • Mac OSX 10.5 or later includes USB 2.0 Audio driver, so no download is required
  • 16-15/16"W x 4-1/2"H x 16-1/16"D
  • weight: 16.5 lbs.
  • warranty: 2 years
  • Our 60-day money-back guarantee
  • If connecting to a TV, please make sure you can select "PCM" output in its audio menu. This DAC cannot decode multi-channel Dolby® Digital signals.

Cambridge Audio 851D Reviews

Average Customer Review(s):

(2 Reviews)
rewards card

Submit a review and enter to win a $350 rewards card

Review this product

Thanks for submitting your review

Most reviews are processed and published within 5 business days. You will receive a confirmation email once your review has been published.

Your Review

Use the stars below to rate the overall product on a scale of 1-5
Upload your photos

Not visible. Email associated with order.
(e.g., Charlottesville, VA)

Additional Fields (optional)


By submitting this review, you agree to our terms and review guidelines.

Filter by rating

Customer photos

<< >>

Hands-on research

Product Research


Twin Analog Devices 24-Bit DACs: The Cambridge Audio 851D employs two very high-quality Analog Devices (AD1955) 24-bit DACs in dual-differential mode for superior sound-staging and stereo imaging. Since each channel has its own DAC to process information, completely separate and symmetrical analog filter circuitry can be implemented. This implementation allows both the left- and right-channel circuitry to operate identically, ensuring the 851D delivers fantastic sound-staging and stereo-imaging properties.

ATF2 (Adaptive Time Filtering) Upsampling: All stereo sources can be upsampled to 24-bit/384kHz and kept jitter-free by proprietary, second generation ATF Adaptive Time Filtering algorithms co-developed with Anagram Technologies of Switzerland. ATF2 Upsampling allows digital audio signals from virtually any audio source to be upsampled, resynchronised, and retimed for extraordinary levels of detail. In effect, upsampling the digital data stream (up to 24-bit/384kHz) allows your  digital music files (from MP3 to high-resolution downloads) to have the enhanced audio clarity, richness and dynamic range that would normally be associated with SACD or DVD-Audio discs. Three proprietary technologies are included in ATF2 effectively reduce noise artifacts caused by imperfect digital systems and allow the digital signal to closer represent the true analog sound of the studio mastered audio data.

  • Adaptive Time Filtering: Adaptive time filtering allows the system to adapt to small fluctuations in the systems audio master clock. The master clock is the heart of any digital audio system, however as all components that are constructed from physical materials, they will at some point in time deviate from their ideal generalized behavior causing, in this case variation in frequency and system jitter in this important internal timing reference. Typically these variations will not be corrected for, however in ATF2 enabled devices the system automatically adapts to these small fluctuations resulting in perfect "glitch" free analog sound even after endless hours of continuous playback.
  • Jitter Suppression: Jitter Suppression allows any incoming audio stream to be resynchronised and retimed to a local very high quality clock. By using a stable-reference oscillator, the negative effects of inter-component jitter can be dramatically reduced. When converting the digital audio to an analogue signal through high performance D/A converters, this reduction in jitter has enormous benefits in the level of detail and clarity in the reconstructed analogue sound.
  • Time Domain Model: Combining this process with a time domain model using an advanced cubic interpolation algorithm, the unique ATF2 system upsamples all incoming audio to 24 bits at 384kHz whilst applying noise shaped dither and is able to actually increase the linearity of response of the D/A converters. The end result is tighter, more focused bass, increased stereo imaging, focus and separation for all musical instruments and voices.

Phase Filter Select: The 851D's ATF2 Upsampling technology employs Cambridge Audio's own proprietary digital filter algorithms with three different filter options available - Linear Phase, Minimum Phase, and Steep. Controlled from one switch on the front-panel, they are extremely clever audiophile topologies specifically developed for audio playback and all offer excellent sound quality, but differ slightly to appeal to a wide range of listening tastes.

  • Linear Phase Filter: The Linear Phase Filter uniquely features "constant group delay" which delays all audio signals at all frequencies by the same amount, meaning all audio is fully time-coherent at the output.
  • Minimum Phase Filter: The Minimum Phase Filter does not feature constant group delay, but rather has been optimized without feed-forward so that the impulse response exhibits no pre-ringing in the time domain. Many audiophiles have argued that the pre-ringing, as seen in nearly all digital filter designs, may affect the transient attack of percussive instruments. Minimum phase implementation eliminates "pre-ringing".
  • Steep Filter: The steep filter removes undistinguishable artifacts via re-calibration for a very slight roll-off at 20kHz, but an ultra-steep drop to the stop-band just after 20kHz.

Asyncrhonous USB Type-B Port: A rear-panel asynchronous 24-bit/192kHz USB (type-B) port enables the 851D to be connected to your Windows PC or Mac computer. An asynchronous USB audio input means that the 851D acts as a high quality external soundcard, allowing bit-perfect transfer from the connected computer to the 851D,
ensuring all data is delivered in perfect timing for the highest possible sound quality. The 851D supports USB 1.1 (Full-speed), USB 2.0 (Hi-Speed), USB 3.0 port-types. The 851D also supports USB protocols 1.0 and 2.0, which are different than USB port-types.

  • PC Compatible: With the 851D switched to USB Audio protocol 1.0 (this is the default setting), the 851D will work with the native Windows XP, Vista or 7 Audio 1.0 driver (no need to load any new driver) and accept audio up to 24-bit/96kHz. With the 851D switched to USB Audio protocol 2.0, the 851D needs the Cambridge Audio USB Audio 2.0 Driver to be loaded and can then accept up to 24-bit/192kHz (and support ASIO and WASAPI Exclusive if required).
  • Mac Compatible: No extra drivers are required to connect your Mac computer. With the 851D switched to USB Audio protocol 1.0,  the 851D will work with the native Mac OS-X 10.5 (Leopard) or above Audio 1.0 driver and accept audio up to 24/96kHz. With the 851D switched to USB Audio protocol 2.0, the unit works with the native Mac OS-X 10.5 (Leopard) or above Audio 2.0 driver and can accept audio up to 24/192kHz.
Note: A Ground Lift Switch enables the USB interface to be disconnected from the 851D chassis ground Disconnecting (lifting) the ground can be useful if electronic hum is heard through the speakers when the USB input is selected. The switch should otherwise be left in the Ground position.

Digital Inputs/Outputs: The Cambridge Audio 851D is fitted with two coaxial (RCA), four optical (toslink), one BNC coaxial, and one AES/EBU (XLR) inputs. The DAC's digital inputs support two-channel PCM audio signals only. If you connect a DVD player or similar device, please ensure that the audio output of the player is set to two-channel PCM (not Dolby Digital/DTS). The coaxial, BNC, and AES/EBU digital inputs support up to 16-24 bit, 32-192kHz audio signals. The optical digital input only supports 16-24 bit, 32-96kHz audio signals. A rear-panel digital optical and coaxial output  allows pass-through of the selected digital source for recording purposes (no up-sampling performed). These outputs loop or pass-through unprocessed digital audio from the selected digital input.

Bluetooth Audio Streaming: Simply plug in the included BT100 Bluetooth audio receiver into the 851D's rear-panel USB (type-A) port for wireless music streaming from many of today's most popular Bluetooth supporting devices; such as iPod touch/iPhone/iPad, Android smartphone/tablet, and Windows/Mac computer. The BT100 even supports the high-quality Bluetooth aptX CODEC, so you can stream audiophile quality music from your Bluetooth-enabled source device to the 851D.

Balanced & Unbalanced Analog Outputs: The Cambridge Audio 851D features both unbalanced RCA and balanced XLR outputs. XLR is a higher-quality output that can reject noise and interference when combined with high-end equipment that offer balanced inputs. The 851D can be connected to Cambridge Audio's 851E stereo preamplifier (779851EB, sold separately) or other brand of preamplifier (sold separately). Because the 851D can also be used as a digital preamplifier, it can be connected directly to Cambridge Audio's 851W power amplifier (779851WB, sold separately) or other brand of amplifier (sold separately). Connected directly to a power amp, the 851D can be used to control volume and balance levels. This clever feature, processed completely using digital technology, facilitates the simplest of audio replays systems and offers amazing flexibility. This function is operated using Blackfin DSP (Digital signal Processor) and gives the highest quality of digital volume control, as opposed to analog attenuation or digital bit reduction.

Headphone Amp: The Cambridge Audio 851D features a built-in, low distortion headphone amp with a front-panel 1/4" headphone jack to connect a pair of headphones. When headphones are connected, the other analog outputs are muted. Use headphones with an impedance of 12 to 600 ohms.

All-Metal Chassis: The 851D features a full metal casework design with thick brushed aluminum front panel and dual layer damped feet, giving enhanced resonance control.

Front-Panel LCD: The 851D has a front-panel display that shows the current status and allows you to access the 851D' system settings menu. Here you can adjust the listening settings of the DAC to your personal preference. The menu system is easy to navigate and control from the remote or DAC. You can adjust the brightness of the display.

IR Remote: The 851D is supplied with an IR remote control that wirelessly operates this DAC, as well as other Cambridge Audio 851 series products and Stream Magic gear (sold separately).

Remote Control Inputs: The 12V trigger output (3.5mm) can be used to control external devices such as an 851W or another power amplifier, or a subwoofer, projector, screen etc. The 851D also features a IR Emitter input (3.5mm) which allows modulated IR commands from multi-room systems or IR repeater system to be received by the DAC. In addition, the 851D features a Control Bus Input & Output (RCA), which allows un-modulated commands from multi-room systems or other components to be received by the DAC and loop out to another unit. The 851D's RS232 port is used for control of the DAC in custom install situations from an external controller

Auto Power Down: The 851D will power down after 30, 60, or 120 minutes of inactivity. This feature can also be turned off.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

The equipment that I was looking for at excellent discounted price. [ Luis  Jun 05, 2016 ]
I chose this due to the excellent reviews, comparing it against other quality DACs in similar price points, and because it has the combination of features I desire: Volume pot, lcd display, headphone out, XLR outs for studio monitors, USB input, and above average DAC components. I'm not an audiophile, just a music enthusiast, so I tend to care less about the audiophile nitpicks on which DAC chip is used, what the output stage looks like, etc. I just want a great DAC from a reputable company. [ Brent  Jun 01, 2016 ]