It gets harder every time it gets smaller, so RU6 marks Cayin as masters showcasing how they can make it work. Descended from R01, RU6's chain of 48 resistors imparts a fidelity to mobile audio not yet experienced.
Your music will be decoded up and down RU6's ladder of individual resistors, crammed into its thumb-sized chassis over two separate six-layer PCBs.
We pay attention when Cayin implements RU6 ala typical R2R – with a NOS (non-oversampling) mode. That's double the feat because the precision demanded goes up. Amidst minimal digital filtering, R2R's analog-like goodness gets delivered unmolested to your ears.
Lovers of reference sound need not fret, however, with RU6's ability to switch from NOS to oversampling mode for the cleanest possible result. That scrubs any last distortion and artifacts beyond the audible human hearing range, leaving you to just enjoy your music, naturally, via one more Cayin innovation yet.