When a new test device arrives in my little audiophile world, two hearts beat in the author's chest. On the one hand, there is curiosity about the candidate's performance, which prompts immediate use. On the other hand, there is the realisation that a longer burn-in period before the first serious listening session usually pays off. Most of the time, reason prevails and the newcomer plays quietly and unnoticed on the living room system for a week. Sometimes, however, the interest is too great and the test object ends up directly on the reference system in the dedicated listening room. This was the case with the new top-of-the-range U2x streaming bridge from Lumin. The decision was helped by the knowledge that the Hong Kong-based company puts every device through a hundred hours of operation before it ends up in the product box. 

My impatience was also justified because the excellent Aurender A1000 streamer had recently impressed me in the same place, and I still had its qualities fresh in my ears. But when the Lumin U2x took its place in the Solidsteel S3-5 rack and I selected Fink's album ‘Beauty In Your Wake’ via Qobuz (FLAC 24-bit/48 kHz), as I had done with the Aurender, I couldn't believe my ears: it was – to put it in North German terms – a different kettle of fish. The sound detached itself even more from the loudspeaker in its three-dimensionality, plasticity and spatial illusion than I was used to. In addition to this great freedom, it radiated a serene calm and underpinned this naturalness with a distinctive and precisely crafted low frequency. Even at first contact, it was clear that there is still room for improvement in the high-end sector that components in lower price ranges cannot achieve, despite all their qualities. The better is the enemy of the good. 

As clear as the gain is – it has to be that way. After all, the Lumin U2x costs almost three times as much as an Aurender A1000 and also does without an integrated DAC. As a pure network transport, the U2x forms the interface between locally stored or Internet-sourced data and a separate D/A converter that serves the analogue signal to the amplifier. Its most important task is to forward the audio files as ‘undamaged’ as possible. At first glance, this may not sound very demanding and is therefore often underestimated. However, staying true to correct timing in the data flow and blocking potential sources of interference is no easy task. Experience shows that this is where the wheat is separated from the chaff. Even the best downstream electronics cannot adequately compensate for suboptimal processing at the source.

In this product group of network transports, also known as streaming bridges, the U2x is the new top model in the Lumin portfolio. It brings together the brand's mature, up-to-date expertise, which has been extremely successful in the field of high-end digital audio playback since 2013. Naturally, the Lumin engineers have built on the experience gained with its predecessors for the U2x, but they have also incorporated new insights, utilised the latest technologies and drawn on their full potential in almost every respect. It starts with the housing. This is CNC-milled from a solid aluminium block in a curved line. Not only does this look very tasteful, but its primary purpose is to dampen harmful vibrations inside and prevent them from entering the device from outside. This consideration continues with the external power supply, which is housed in an equally manufactured, maximally rigid aluminium enclosure. Recognising the importance of the power supply for the final sound quality of a digital audio component, it has been designed as a linear power supply and is extremely sophisticated: two toroidal transformers with three rectifier bridges and five very low-noise analogue voltage regulators form the basis for the operation of the U2x.