It's impressive how Fiio has considered the upgrade path for E7 DAC owners by integrating an iPod-style dock connector into the E9. For my own extensive use, since I am almost exclusively on UAPP bitperfect or HiBy Music Player USB Exclusive Mode, the NOS option proved to be the better choice.

According to Cayin, that presented a challenge of picking the volume control with higher precision, lower noise, and less power consumption. I haven't had that same level of uppermids harshness since then, and initial warm-up period was only a minute or two as this unit is quite small and getting it up to operating temperature should be quick. The net result is a potent and respectable 138mW per channel into a 32-ohm load or 213mW through the balanced output, nothing to scoff at from a compact portable source. After spending 2 months of testing RU6, plus a ton of posts I made and questions I answered on Head-fi about it, it’s time to summarize everything in my full review. There is a small pinhole vent ahead of the 2-pin connectors, not sure if this is actually for tuning or letting the sub-bass drivers breathe or pressure adjustment.Hi, saying “RU6 does have a more natural warmth and body while W2 tilts the scale in the opposi Don't get me wrong, it is already admirably smooth, but comparing it against Lotoo PAW S2, Ovidius B1, Apogee Groove and CEntrance DACport HD, I can hear that RU6 favors crispness slightly more over smoothness.

There are no pops when powering the dongle on or off which adds to the refinement of the overall user experience. Still for a device featuring an R-2R network and resistor array volume control, it is quite compact and lightweight, not that larger than the FiiO KA3. On the other side of the spectrum, RU6 is as amazingly competent driving super sensitive stuffs like multi drivers hybrid IEMs. The hardware has been designed in an intuitive manner, where the volume buttons double as menu selectors and the OLED screen displays playback information accurately.In fact when paired with my ER4SR and Shure KSE1500 I am hearing every micro details that are available in the recordings. The Cayin Ru6 delivers the R2R performance within a very portable size and the tonality is comparable to any R2R DAP. You can often see manufacturers emphasizing the volume control chipsets, a vital component in the signal path that may degrade the sound and mess up the dynamics if poorly implemented.

U18t does present you with a more forward and more revealing tonality, but in pair up with RU6 it sounds less harsh and a lot less fatigue in comparison to some other sources. Having got back into headphones recently I was intrigued to see if there was a portable equivalent, and found the RU6. The very expressive midrange on RU6 performs really well with indie rock, slow jazz, old pop songs, and house music. The RU6 is prone to picking EMI interference from a phone that causes background noise which can range from a faint hiss to a louder humming especially when using more sensitive earphones.One of my favorite albums is entitled "Hush", a fuse with Nora Fischer singing baroque arias accompanied by the electric guitar of Marnix Dorrestein.

Enthusiasts will be sure to enjoy the RU6’s wide stage and analogue-like note presentation that grant it one of the sweetest and most euphonic sounds I’ve encountered from a portable source yet. To combat this, Cayin spent 3 months developing a custom resistor volume array that provides 99 steps of volume through 9 segments of resistors and switching relays. That means you can plug it into your laptop, iPad, or phone as well as DAPs and enjoy R-2R decoding. Adding Cayin C9 amp beefs up the bass a bit with more weight in sub-bass and mid-bass, but even without C9, it was still a great pair up.However, they often ended up being too clean sounding that they lacked musicality and some even lacking realism altogether. This architecture minimises power drain from the mobile source allowing you to enjoy music without the need to worry about battery drain.