Having become financially independent (after 6 years of uni and 1 year of internship) I finally took the plunge and requested a custom pair of IEMs. More about them later.

However, this decision entailed getting a completely new source, since my main players of choice up to then were: Sansa Clip+ and my phone (Xiaomi Mi 9T Pro).
Those wouldn't quite do, right?

So, after thinking out loud what my needs are, I realised that it'd be nice to have some device that is quite portable and can be used to enhance audio coming out of my PC, as well.
At first I thought about getting some DAP (either Shanling M0 or Fiio M5), but then I remembered that I had had a short fling with Fiio M6 and hadn't been quite satisfied with it, when it came to ease of usage and its performance (apps felt a bit laggy, the latency in DAC mode was noticeable). That's why I opted for a AMP/DAC combo.

And that's exactly how I got to know Qudelix-5K.

On paper it seemed to check all the boxes.

What's the catch? one would ask. Well.. It's availability.
At the time it was nowhere to be seen, especially in Poland, Europe.
Almost every second-hand copy sold in a matter of hours. Some eBay resellers tried to list them at 300% MSRP.

I waited patiently for a few weeks since my CIEMs were in the works. Time has passed, but nothing changed.
Finally I decided to contact Qudelix directly and ask when the next batch can be expected. Few days later I got a reply stating that it's back in stock, but at the same time they advised me to hurry, because it wasn't that big of a batch.

I didn't think twice and made the purchase almost right away.

Shipping via FedEx was quick and quite swift - it took only 7 days to get from South Korea to Poland. It's worth noting that FedEx reached out to me to correct some custom forms, but everything was sorted out when I sent them a confirmation of payment and the order summary.

Qudelix-5K was finally in my hands.
First impressions: whoah, it's really tiny! Size-wise it looks almost like my Sansa Clip+, if not a little bit narrower.

Build quality is superb. It feels very durable. No squeaks, no loose elements. The clip features a snappy spring and makes the device even more usable.
The body itself, thank God, isn't glossy. (Looking at you, Fiio BTR!) The matt finish makes the 5K quite grippy and saves it from gathering all the fingerprints.

Many reviewers have already complained about the buttons and, sadly, I have to join them, too.
I've been using it for almost two months on a daily basis, and yet - every time I want to press a button, I need to stop for a while, think, make sure it's the correct one, because it's so easy to mistake them.
It's a shame Qudelix didn't try to somehow make them differ from each other - be it in shape, placement, etc.
Having said that, clicking the buttons feels good - they are tactile and make a little sound when pressed.

When it comes to using Qudelix-5K, things couldn't be made easier.
It's just a matter of downloading a companion app to your device (even PCs have a dedicated app, which works as a Google Chrome /Chromium extension) and pairing them both together.
The app itself is quite clear and offers a lot of settings to tweak - both power- and sound-related.
The EQ tab is so extensive and so customizable that it really should satisfy everyone's needs. It definitely made my little, non-EQ head hurt.

Can't say any bad word about 5K's stability and/or performance.
When connected to my PC via USB C (I do recommend getting a magnetic plug for it, makes your life whole much easier) it immediately starts working as a main audio device. So far, I haven't experienced any glitches or anything like that. Latency is good.
It's worth mentioning that Qudelix lets you choose if you want your device to auto power on/off when connected to a charging source and that they made sure 5K draws power directly from USB when working as an USB DAC. I love that.

Bluetooth connection, especially its range and stability, also need to be praised.
I can safely roam through my home with no audio drops, even though I'm sometimes four walls away from the source.
5K communicates with my Xiaomi phone with no issues - it can control music playback and lets me answer my calls, all the while acting as a mic since the earphones I use don't have one.

So far, I didn't really have to plug it to a charger during the day - the battery life is more than enough, even when I travel. Connecting it to a PC for some one-hour listening session in the evening replenishes all the juice it needs.

Re: sound quality - here's where I have to disappoint you: I need to admit I don't have much (well, almost any) experience when it comes to audio devices, especially AMPs or DACs.
That's why I don't feel qualified to say how it does on this field.

What I can tell you for sure: it definitely brings some depth and clarity to all the files I throw at it. It's unbelievable that even some 64 kbps tracks (don't ask..) had something hidden in them and Qudelix-5K made it magically reappear.

I guess that's all I had to say..

Feel free to ask me any questions!