Disclaimer: Cozoy is a sometimes-customer of mine, and for whom I shot the advertising image seen above. As such I will not write a subjective review of REI here or at Headfonia. It also means that the unit I have in my hands came at no charge to me. It is a working, production unit. Considering the above, please remember your salt.
Considering Astrapi’s abortive attempt at audiophilia, I expected little of REI. Instead, COZOY have corrected every of Astrapi’s egregious faults. They are: REI outputs no more hiss than an iPhone 6; its lowest volume levels jive with sensitive-eared listeners; it outperforms the iPhone 6 in a number of key metrics; it gets loud without turning its signal to mush.
I have no idea what REI will cost. I don’t know its full spec. I know only that it looks like an Alien, and that it performs well. It also decodes DSD up to DSD256. Finally, at 0,033% and 0,050%, it has higher THD and IMD levels than the iPhone, than the AK380, and most respectable DAPs out there. Single-ended, Onkyo’s DP-X1 measures similarly. That said, 0,033% THD and 0,050% IMD should be inaudible to all but audio analysers.
Pushing REI to volumes which match the DP-X1’s and AK380’s incredible outputs - and which require me to pad my Lynx HILO’s input @ +6dB - exponentially drives artefacts north. Of course, this is true for every DAP/smartphone, and DAC/amp. And, you won’t be listening to earphones or portable earphones through REI at full volume. You’d be deaf in short order. Nevertheless, loaded (Earsonics SM2) @ max volume, REI’s base IMD jumps by 264x; THD jumps by about 3x. The latter is of no consequence. Largely, its IMD troubles sort themselves out when REI’s lowered to match an iPhone 6’s maximum output. And I doubt that the idiot listening to sensitive earphones at such volumes would notice artefactual IMD of 13% let alone 0,5%.
Keep in mind that neither the software (RMAA) nor the hardware (Lynx HILO) are optimal benches for testing outputs of amps and DAPs. Still, by the numbers, REI puts to shame today’s best smartphones and even surpasses a number of high-end DAPs, some of which cost thousands of dollars and are slaved to interfaces and indexing systems that botch gapless playback and natural haptic interfaces. REI is tiny and works seamlessly with your iPhone, PC, and more.
I only wish it had a clip.
The following Rightmark Audio Analyzer tests were conducted through this equipment.
NL - no load
SM2 - Earsonics SM2
ES7 - Audio Technica ES7
DT880 - Beyerdynamic DT880/600
24-bit TARGETS and loads +0dB (volume matched to iPhone 6’s maximum).
REI is impressive. Assuming performance remains top-notch, I’d love to see it go balanced.