New kid on the block: Stack Audio’s Onset

“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” – so trails Stack Audio’s introduction to their ‘no compromises’ network streamer, the Onset.

They’ll meet with no objections here. Jitter and electrical noise being the fork-tongued foe of better sounding digital audio is well known to DAR’s regular readers.

My introduction to this new British company came via email from one Theo Stack: “My name is Theo, we have developed a music streamer called the Onset. Would you kindly consider posting our press release for us on your website?” Clean and simple. Hit me.

Alas, a press release wasn’t forthcoming. Only photos and a .pdf with text directly copy/pasted directly from his website:

“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.”

That’s the theory taken care of. How about reality? This photo gives us a look-see under the Onset’s hood:

The mainboard, transformer and multi-regulated dual-rail power supply (one rail for a pair of clocks, the other rail for the DSP) are housed in a single piece of machined aluminium and are walled away from each other to minimise electrical noise’s cross-contamination.

The back panel shows two inputs – Ethernet and USB – nestled amongst a range of outputs: PS Audio- / Wyred 4 Sound-compliant HDMI I2S, S/PDIF coax and (singe & dual wire) AES. BNC sockets invite the addition of an external clock. Does Theo Stack have a pro audio heritage, I wonder?

“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.” This suggests the Onset’s firmware is field updatable.

For music playback, the Onset plays catch on UPnP streams and yes, gapless playback is guaranteed from the outset.

Remote control will eventually come from Stack’s own iOS/Android apps, which are still in development. Until then, users are directed to old standbys like Bubble UPnP (Android), JRiver (Windows, Mac) and Twonky (Windows, Mac).

On possible Roon Readiness, our man says, “The Onset is not Roon Ready. We use a Swiss made module which is ultra low noise and EMI [sic] but the chip cannot support Roon. The Swiss company are working on a new module that will support Roon and MQA. However, a delivery date is still to be confirmed. So I am not making customers any promises. The fact that it does not support Roon is reflected in the price, if it did support Roon it would likely cost twice [sic]”.

Hooking a third party PC/Mac/streamer into the Onset’s USB input and a DAC to its coaxial output turns this streamer into a USB-S/PDIF converter. That’s a nice touch.

The Stack Onset sells for £3234 (inc. VAT) and is available in silver and black (on request for a £50 premium).

Further information: Stack Audio