USB Network bridge/Reclocker 

The LINK II is a digital audio bridge that accepts music files streamed from internet subscription services or music files you already own and links them to your hi-fi system.

Stack Audio is focused on the source. Introduce noise and distortion at the start of the playback process and it disrupts the enjoyment of the music. The LINK II has been built from the ground up to remove unwanted noise. Your favourite music sounds more realistic and immersive. 

Computers are plagued with noise

You can take a digital signal straight from a PC or laptop and connect it to a DAC. However, computers have many integrated circuits and power supplies, tightly packed together, and running software that generates noise.

This can damage the critical phase and timing information in music data with a perceived reduction in dynamic contrast and a loss of musical nuance. This is known as jitter. Human hearing is very perceptive to phase/timing accuracy, and it is vital to a true analogue representation of music. Eliminating jitter and achieving true phase accuracy was John Westlake’s focus when designing the LINK II making it the best way to connect your streaming sources to your DAC.


S Power

Power supplies are essential to energise circuits and make electronics work. Everything starts with power. However, if they are not implemented well, they can add noise and distortion.

Stack Audio’s approach is two staged. The first stage is the VOLT – a separate external linear DC power supply. This removes background noise, revealing subtle details often masked by generic switch-mode power supplies. The second stage is an advanced, low noise, power supply stage inside the LINK.

The VOLT uses high quality components throughout to minimise mains noise and provide 18V of pure, smooth, linear DC:
  • UK made precision wound Toroidal transformer
  • Audio grade capacitors and connectors
  • Noise suppression filters on both the input and output signals
  • Precision machined aluminium case
  • Transformer mounted on an isolation plate incorporating AVDC
  • High-quality star-quad geometry connecting cable provides protection against EMI and mains borne interference
The LINK features a purpose designed, low noise, multi-stage power circuit:
  • Three independent switching regulators are synchronized to the audio clock. This ensures that the fluctuations of the switching circuit are in time with that of the audio clock reducing fluctuations and noise interference
  • Nine organic low resistance capacitors help filter and purify the power
  • A triple linear regulated circuit purifies remaining noise
  • The USB audio output and clock circuit has its own independent power rail

S Clock

What is a clock circuit and why is a good clock circuit important?
A clock is the heartbeat of any digital device. In the world of digital audio, multiple clocks running at different speeds cause noise and jitter problems. We typically hear this as an edgy or brittle quality to the sound.

The accuracy and reliability of the clock system, has a huge influence on the performance of the product. The LINK II uses an ultra-low phase noise oscillator powered by an exceptionally clean supply. The ethernet, USB and the PSU are synchronised to the audio master clock, resulting in one coherent and extremely accurate device. This ensures that the fluctuations of the switching circuit are in time with that of the audio clock reducing fluctuations and noise. 

Solid Aluminium Case

The LINK II is a pure digital system housed in a solid CNC machined aluminium case enclosed with EMI absorbing material. This ensures noise does not escape and enter the analogue domain nor does noise enter and affect the clock circuit.


The LINK II is designed to be as easy to use as possible. You do not need to download new software or learn a new control app to make it work. You can continue to use your favourite and familiar software to control and send music to the LINK II.  The LINK II works as an endpoint for the following protocols/programs

  • Roon (Roon Ready certified) 60 day trial included 
  • Audirvana
  • Squeezelite
  • Airplay® (Shairport-Sync )
  • Spotify® (Librespot)
  • HQPlayer 

Can’t decide on your control software? Click here to find out more.


*For further information please click here 


Audio Feature Summary
  • Power circuitry is synchronized to the USB audio clock
  • Ethernet input is synchronized to the USB audio clock
  • Multi-stage ultra-low noise linear regulated power circuit
  • USB audio optimized output provides jitter free audio layback
  • The advanced clock circuitry re-clocks any USB input
Mechanical Feature Sumary
  • Machined from a solid billet of aluminum
  • Incorporates EMI absorbing material to remove internal EMI
  • The mass of the case dissipates air-borne vibration
  • Incorporates AVDC vibration trap
Communication Protocols
  • Ethernet
  • USB
  • Wi-Fi
  • Bluetooth
  • 1 x dedicated USB audio output
  • HDMI out (not i2s, or used)
Streaming Protocols
  • Roon
  • Audirvana
  • Squeezelite
  • Airplay® (Shairport-Sync)
  • Spotify® (Librespot)
  • HQPlayer (coming soon)
Supported Audio File Formats
  • Lossless: DSF (DSD), DIFF (DSD), DoP (DSD) DoP and Native DSD up to DSD 256
  • PCM Lossless: FLAC, Apple Lossless (ALAC), WAV, AIFF Compressed (lossy) Audio: MP3, AAC (in M4A container) MQA (only if DAC supports hardware unfolding) PCM up to 384 kHz /32 bits
  • Finish : Available in anodised silver or black
  • Dimensions: 174mm(W), 140mm (D), 25mm (H), 1kg (without external power supply)
  • 2 x USB inputs (Future use)
  • 1 x USB B detox input
  • Ethernet input
  • 18v 1amp- 1.5amp DC input

Made without compromise.
See what goes into making a LINK II

Press Reviews

Customer Reviews


I want to try the LINK II before I decide it’s for me?
We are really confident in the performance that we offer a 30-day money back Guarantee – see our Terms & Conditions
I do not understand what the USB power switch is for?
Not all DACs require power from the USB input, so the LINK features a USB power switch. The USB power feed is no longer active alongside the data line when this is switched off. If you’re not sure if your DAC requires power through the USB, try it switched off. If it still plays your DAC has its own power supply and the sound will benefit from having the USB power signal turned off.
Does the LINK II come with USB/Ethernet cables?
No. User requirements vary in terms of connector length and quality. We leave the choice to the user. The LINK ships with an 18V DC power supply and region appropriate plug.
I don’t use Roon. How else can I control the LINK II?
You can use the Stack Audio web interface on any device connected to your router with a web interface. You can also use third party control interfaces such as Bubble UPNP for Android and Jremote for iOS.

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