I trialed my friend's 5K while owning BTR5, for my on-the-go pairing with my IE900. After 2 weeks of test, I decided to purchase the 5K. There's several reason why I preferred 5K over BTR5 and here's my quick review.

PACKAGING
I appreciate how Qudelix presented this. Yes, some might complain it's not as premium but heck, it save on material and shipping. I don't need wooden box, microfiber gloves and 100 pages of manual. Ok, maybe a silicon case will be great since I can't find any case for it.

HARDWARE AND DESIGN
Think of M series vs 7 series of BMW. 5K is the M series. Performance and durability first. Good plastic construction that give confident it will survive in my pocket or my bag. This thing feel like a tank without feeling overbuilt, bulky or unnecessarily heavy. The clicky buttons work well in blind without much confusion for me. Overall remind me of my old Sansa player. My previous daily driver BTR5 is thinner and longer in dimension however with case clip on, it's more bulky. Yes it's more premium and with fancy OLED but without the case, good luck not breaking it due to slippery sandwich glass construction. Come with 3.5mm and 2.5mm output but I wish it's has 4.4mm jack instead as most of my cables 4.4mm terminated. Otherwise a solid A in my book for hardware and design. I won't change one thing on the hardware.

SOUND AND POWER
This is upgrade over BTR5 for me, in term of usability, function customization and output power. The tuning is quite neutral. Great DAC implementation. The 2V over 3.5mm and 4V (!) on 2.5mm ensure nothing but electrostat will be drivable to good level. Minimal hiss on both ends too. If anyone unable to get listenable volume on the go with this device, definitely nothing else will do for you, provided you need BT function. I yet to try iFi go Blu though. BT reception seem better compared to my BTR5, no dropout at 10m unlike BTR5 which start to clip and lag. Combined with software prowess, you can adjust and adapt the hardware and sound to your liking.

SOFTWARE
Software is the one of the pillar of Qudelix 5K. Nothing come close to this app among it's peer. Buck load of customization that some might find it too overwhelming at first. Each tab come with multiple submenus for customization. Suggest to go slow and read the accompanying description on each page to understand the function. With PEQ, you can change the profile to your liking. There's also Auto-tuning function (download from database through app itself!) which is great addition for newcomer to start screwing their sound profile. Beside the sound customization, there's also lots of control over USB/BT and CODEC priority, sleep and charging behavior, battery care and over 9000 other functions. It might be too much for some but you can ignore it and it still work great.

MISC
5K has built-in mic and a great one at that. This enable voice call and even transparency mode (so-so in my experience, depend on where you clip it). I also wish it has some kind of IP water resistant rating since this is intended for on-the-go usage.

In conclusion, at around USD110, this is a solid performer among the currently available BT dongle option. Main strength are output power and software.


Qudelix 5K next to his portable home DAC/AMP, the R2R Cayin RU6. I wish Cayin have made RU6 with some kind of wireless function. That will be interesting!