Introducing The Onset

The Onset is a state-of-the-art network music streamer that sets new standards in digital audio playback.
Specifically designed to act as a bridge between your network and DAC, the Onset is the result of three years of intensive research, design and development by new British company Stack Audio.

The company has made no compromises. The finest components have been transformed into a ground-breaking system using advanced automation and traditional hand craftsmanship.

The goal? To deliver advanced digital sound quality with a new level of fidelity that rivets the most discriminating audiophiles and music lovers.


Jitter and common mode noise in the audio signal are key challenges in digital audio and all-too-frequent culprits in marring or limiting the listening experience. The Onset features a combination of advanced technologies designed to solve the problem from the outset. First, a unique power supply achieves the perfect audio signal by ensuring that the audio circuitry is never in contact with the mains source, alleviating the need for excessive filtering which can otherwise restrain sound quality. Second, rather than seeking to minimise jitter, the Onset’s advanced asynchronous low-skew clocking system eliminates it from the outset. Its pioneering upgradeable digital processing platform has been custom-designed to extract the best possible performance from the Onset’s two ultra-low phase noise oscillators. Noise? History.


The Onset’s sleek bodywork is precision-machined from a special aerospace-grade aluminium and finished to an exacting standard. As well as providing an elegant and robust housing, the casing also delivers effective isolation from both mechanical and EMI interference thanks to its individually machined compartments for the circuit boards and transformer.

Key features

  • State-of-the-art Stack Audio digital processing platform which can be easily upgraded to add new features and support new formats.
  • Low-noise design enables bit-perfect data transmission and two-channel asynchronous streaming for jitter-free stereo playback.
  • Supports up to 24bit 192khz PCM as well as DSD over DOP. Future updates will enable playback of DXD 384khz (over dual wire) and native DSF and DFF files.
  • Ultra-low phase noise oscillators measuring in the low femto seconds.
  • Supports studio-level clock syncing and dual-wire AES mode used to separate transmission of left and right channels in leading digital-to-analogue converters for ultimate fidelity.
  • Asynchronous USB to SPDIF converter vastly improves the sound quality from your USB source.
  • Bespoke ‘Never Connected’ power supply isolates the Onset from the mains, eliminating the adverse effects of mains pollution.
  • Multi-regulated linear power supply with two separate power rails - one for the sensitive clock circuitry and another for the DSP - to help eliminate ground loops.
  • Individually machined pockets for the circuit boards and transformer, plus added vibration dampening pads, to isolate both mechanical and EMI interference.
  • UPNP™ compliant and gapless playback supported.
  • Available in Black upon request.

Technical specifications


Digital outputs

2 x AES EBU (single or dual wire), 1 x SPDIF (coaxial), 1 x i2s via HDMI (for use with high performance DACs such as PS Audio, Wyred4Sound)

Digital inputs

1 x RJ45 connector network interface
1 x USB 2.0 interface type B connector


1 x BNC clock output
1 x BNC clock input supported frequencies: 22.5792, 24.576 MHz; 44.1, 88.2, 176.4, 48, 96, 192 kHz


420mm (w) x 250mm (d) x 50mm (h)
16.5” (w) x 9.8” (d) x 1.96” (h)
Weight 7.5kg


Anodised black or silver




Stack Audio app (works with all iOS7 devices, Android version coming soon)
Bubble UPnP (Android); computer control: JRiver (Windows, Mac), Twonky (Mac & Windows)


49-62Hz; 100, 115, 220 or 230V AC

File support

DSD (DOP) 64 is supported by all digital outputs. DSD (DOP) 128 and DXD as well as support for DSF and DFF are all planned to be released soon.

  • ALAC (Apple Lossless Audio Codec)
  • FLAC (Free Lossless Audio Codec)
  • AAC (Advanced Audio Coding)
  • WAV (Waveform Audio File Format)
  • MP3 (Mpeg Audio Layer 3)
  • ALAC (Apple Lossless Audio Codec)
  • AAC (Advanced Audio Coding)
  • AIFF (Audio Interchange File Format)

The Onset is now available direct. MRRP Silver £3234 Black £3294