LINK Streamer 2 - Stack Audio

LINK II

USB Network bridge/Reclocker

The LINK II is a digital audio bridge that accepts music files “streamed” from internet subscription services (like Spotify, Tidal, Qobuz etc.) or music files that you might already own and links them to your HiFi system.

Stack Audio has always been focused on source devices, after all, it’s where everything starts. Introduce noise and distortion at the start of the playback process, it damages and disrupts our enjoyment of the music, as a result, the LINK II has been built from the ground up to remove unwanted noise. Your favourite music sounds more realistic and immersive. The LINK II’s new clock has 50% lower phase noise in contrast with its predecessor, Stack Audio’s LINK.

Computers are plagued with noise

It is possible to take a digital signal straight from a PC or laptop and connect it to a DAC. However, as with analogue systems, digital systems can be plagued with noise.

Computers have many integrated circuits and power supplies tightly packed together with software processes running that generate noise.

This noise easily jumps onto the data bus that is used for moving files through the computer; this is often described as ‘parasitic’ noise which can effectively mask and blur the file being played back. The result of damaging the critical phase and timing information is a perceived reduction in dynamic contrast and a loss of musical nuance. This digital timing error is known as ‘jitter’ and if left untreated tends to give harshness to the sound we hear.

When it comes to hearing we, as humans, are very perceptive to phase/timing accuracy. Phase accuracy is vital to a true analogue representation of your music. Achieving true phase accuracy was John Westlake’s main focus, when designing the LINK II.

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. The LINK II’s advanced digital processors are powered by uniquely designed, exceedingly low noise, multi-stage power circuitry.

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?

The clock system is the heartbeat of any digital system, it manages and creates a mathematical reference for the various protocols to work from, be that Ethernet or USB.

In our world, that of digital audio file playback, multiple clocks, all running at different speeds tend to cause noise and jitter problems. We typically hear this as it gives an edgy or brittle quality to the sound.

The accuracy and reliability of the clock system, therefore, has a direct influence on the performance of the product.

The LINK II uses an ultra-low phase noise oscillator. Here at Stack Audio we went to great lengths to extract the absolute performance from this clock. It starts by powering it with an exceptionally clean supply. In addition to this, we synchronised the ethernet, USB and the PSU 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. The three independent switching regulators are synchronized to the audio clock, thus when the PSU switches frequencies it is in time with the master audio clock removing clashes and interference.

Solid Aluminium Case

The LINK II is a pure digital system housed in a thick 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 Software

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. Afterall companies like Roon, Audirvana, Spotify, Tidal etc. have already invested considerable resources into delivering world class software, which most of us already know how to use.

The LINK II works as an endpoint for the following protocols/programs

Roon
Audirvana
Squeezelite
UPnP/DLNA
Airplay® (Shairport-Sync )
Spotify® (Librespot)
HQPlayer

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

The LINK II is Roon Ready certified!
60 day free Roon trial included with your LINK II

*For further information please click here

Specifications

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

Outputs

1 x dedicated USB audio output
HDMI out (not i2s, or used)

Streaming Protocols

Roon
Audirvana
Squeezelite
UPnP/DLNA
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

Physical

Finish : Available in anodised silver or black
Dimensions: 174mm(W), 140mm (D), 25mm (H), 1kg (without external power supply)

Inputs

2 x USB inputs (Future use)
1 x USB B detox input
Ethernet input
18v 1amp- 1.5amp DC input

User manual (PDF)

VOLT LINEAR PSU

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

Discover more

Press Reviews

HiFi+

“The first thing you notice about this is it’s fast. Transients happen quickly here, a bit like a really well set-up CD player compared with first-generation streaming. Play something with a lot of fast beats (‘Fuzzy Monkey’ by Morton Granau, streamed from Tidal) and it arrives with almost supernatural speed.” Alan Sircom, HiFi+

The Ear

“I am very impressed by the Stack Link II, it offers a standard of sound quality that you expect of a streaming bridge at twice the price alongside the build quality of something more expensive. How many streamers have machined from solid cases at any price? I used Roon for most of my listening and […]

Customer Reviews

Doug L. – UK

“I first became interested in considering using my computer as a playback/streaming device a numberof years ago. I originally used my desktop computer and various Dacs such as Audio Engine D1,followed by Audiolab M and Chord Mojo.I started spending considerable time researching audio playback and equipment through a variety ofmeans, including articles on the internet; […]

David E. – UK

“I was looking for a streaming upgrade to my Bluesound Node 2i. I didn’t need a DAC as I was happy with the on board DAC on my Moon 240i amplifier. Having read several reviews of the Link II and it’s predecessor, I liked not only what was being said about this streamer but also […]

James O. – USA

“I wanted to write to give my impressions of the Stack Audio Link II streamer. I actually upgraded my Link streamer to a Link II. I dealt directly with Theo Stack in returning the Link and having it upgraded, including purchasing the new LPS. Theo is a genuinely nice guy, and it was a pleasure […]

FAQ

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.

Speak to an expert

Europe: +44 (0)1626 24 9005

USA +1 (866) 232 7610

8am-6pm BMT

LINK II

S Power

S Clock

Solid Aluminium Case

The Software

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

Specifications

VOLT LINEAR PSU

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

Press Reviews

Customer Reviews

FAQ

Live Chat

Get in Touch

LINK II

S Power

S Clock

Solid Aluminium Case

The Software

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

Specifications

VOLT LINEAR PSU

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

Press Reviews

Customer Reviews

FAQ

Live Chat

Get in Touch

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

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