My portable/travel music player is a Cayin N6ii player. It's an interesting device as it uses replaceable motherboards. These motherboards contain the DAC chips for the digital-to-analogue conversion.
The motherboard that I am currently using with my Cayin N6ii is known as the E01 motherboard. This uses the ESS ES9038PRO DAC chipset and has a dual operating mode for the amplifier: Class A and Class AB. I run it in Class A mode.
Battery life is pretty good and the player produces high quality sound. The current firmware it also supports MQA, allowing the N6ii to act as an MQA renderer.
An interesting facet of this player is that it uses Android version 8.1.0 but bypasses Android SRC (Source Rate Conversion) at a system-wide level for music apps via its DTA (Direct Transport Audio). This is a great feature as Android resamples audio to 48kHz generally-speaking.
When not being used as a portable player, my N6ii acts as a digital transport to an external DAC via its I2S interface. This is generally a better interface to use for digital audio compared to USB-Audio. At least that used to be the case. I2S provides a more direct path from the source device to the external DAC's chipset.
I've installed the TIDAL app and USB Audio Player Pro (UAPP) onto the N6ii to cover all of my audio listening requirements. The N6ii comes with to 'system-level' music apps: Cayin Music and HiBy Player. Cayin Music app is a more streamlined version of HiBy Player but to all technical intents and purposes, they are the same.
One nice feature of the Cayin Music or HiBy Player is the ability to remote control the apps via HibyLink. This is useful when the N6ii is acting as a digital transport in my headphones system.
I'm using a 512GB Sandisk micro-SD card in the N6ii to store my local files (which are mostly CD-quality FLAC files with a few Hi-Res FLAC files).
My preferred headphones to use with the N6ii are my Beyerdynamic Xelento IEMs. These are very high quality earbuds and a great match for the N6ii. I'm a bit of a Beyerdynamic fan so I'll be doing a post on my headphones collection in due course. The Xelentos are very discreet and fit very well in my ears as they come with various eartips - both silicone and Comply foam ones.
The Cayin N6ii is a very versatile device with USB-Audio out, fast-charging, I2S interface, replaceable motherboards (some of the other available motherboards have specific functions like line-out only, balanced out, etc.), Android OS (albeit a fairly old version now), bypassing of Android's SRC using DTA, ability to install other Android apps, Bluetooth (although I don't use this feature), a good battery life. The processor in the N6ii is a bit of a weak point compared to today's DAPs, but it copes with all of my music playing requirements and I don't notice significant lag using any of the music apps.
Feel free to post comments or ask questions if you have found this post interesting.