Cayin RU6 USB DAC Headphone Amplifier

Product Information

The DAC itself is power efficient so you don't have to worry about draining the host device battery. The Cayin comes standard with a USB-C to USB-C cable, along with a USB-A adapter, but for iPhone users, a lightning cable can be purchased separately. I was trying to resist the temptation to try this, but curiosity got the better of me, and I had to see how this little engineering and packaging wonder sounded. This is the first time that this has been implemented on portable dongle-type decoders such as the RU6. Without hesitation is one of the best sounding and most powerful USB DAC dongles available right now.

The unit offers standard accessories needed to run on the fly with any USB-C devices or PC with USB-A (via included adapter). According to Cayin, while they have realized a growing demand for high end usb dac dongles, they were not satisfied with off-the-shelf DAC solutions for dongle application and were not in a rush with their own dongle. The highs seem like there may be a spike or peak somewhere in the upper mids or treble, but not in a painful way. The sound has a natural smoother tonality, good bass extension with a textured sub-bass rumble, natural detailed mids, a little peaky lower treble but nothing too harsh, treble has a decent airy extension; soundstage is wide; background is black except for a very mild waterfall hissing.steps volume control through 9 segments of resistors and switching relays, meet all the RU6 requirements and transparent to maintain the natural sound signature of R-2R DAC. Due to the way the R-2R circuit is designed, there are moments where the volume with quickly pause and pop. With the midrange being quite forward and the very low end being quite shy, staging is stretched wide.

The basic idea of the R-2R ladder is a matched pair of resistors, the first is “R” and the other is “2R'' which has twice the value of R. RU6 was connected to my Galaxy phone with volume set at the max (on the phone), and I was using HibyMusic app.

Disclaimer: The Cayin RU6 was sent to us free of charge by Cayin directly in exchange for this review. It didn’t sound too bad, but I wasn’t able to drive these headphones to their full potential, and added C9 to the output.

I’ve had the RU6 for about two months and I am really enjoying the sound and life it puts into my legacy stereo system. While based on the specs mW stats this is slightly less powerful than the W2 - but in real life scenario I found this to be quite powerful and can easily power even power hungry IEMs. Within, the user has the option to toggle screen timeout and brightness in addition to toggling NOS/OS modes and low/high gain. Bass could have benefitted from a little boost, but overall, the bass has a deep extension, nice fast punch, mids have more neutral lower mids, clear detailed upper mids and vocals, and detailed crunchy treble with a nice airy sparkle. Again, the bass doesn’t hit very deep so it takes away some of the depth yet it works well for studio-recorded tracks and small ensembles.No artifacts heard, no metallic harshness, no edginess to the sound which in contrast gets close enough to the analogue ideal at least as this is possible for such a USB powered device. Otherwise from quality perspective I found both to be quite satisfying, there are times I want to have solid crispness and solid imaging and the 4. These are mids that give you the entry level to R2R signature - do not expect Ares II performance but the level produced is far different and higher in naturalism than leading MQA dongles. The bass is visceral, weighty but still tight and well controlled, fast, clearly defined and multi-layered.

I spent a short period of time going through Oversampling mode and No-Oversampling mode and decided to just stick with the NOS mode for my music listening, as this provided the most pure form of listening to the R-2R DAC.

Nonetheless, with all my music the RU6 was punchy, full sounding with great macro dynamics from electronic music to classical.