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.
- 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.
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 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
- Airplay® (Shairport-Sync )
- Spotify® (Librespot)
- HQPlayer (coming soon)
The LINK II is Roon Ready certified!
60 day free Roon trial included with your LINK II
- 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
- 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
- 1 x dedicated USB audio output
- HDMI out (not i2s, or used)
- Airplay® (Shairport-Sync)
- Spotify® (Librespot)
- HQPlayer (coming soon)
- 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
LINK LINEAR PSU
Extracts from Alan Sircom’s review of the LINK in Hi-Fi+
“Now, the Dragonfly Cobalt is not an expensive DAC at around £260 but paired with the Link II, it was a combination that I could live with and I don’t mean in an “I guess that might do” sense; this was seriously good stuff.”
Extract from John Scott’s review of the LINK II in HiFi Pig
LINK II + AQ Dragonfly Cobalt + AQ Golden Gate interconnect bundle price £895. Purchased separately £1,063.
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