🔷 Qudelix-5K

This is the official thread for the Qudelix-5K

This thread is for discussion and reviews.

  • 3.5mm & 2.5mm out, Bluetooth up to ldac& type c USB in
  • 2x ES921P, QCC5124
  • EQ

:red_circle: Hifiguides Amazon Link


Z Reviews…


let’s hope portable gear like this adopts the 4.4mm Pentacon and drops that easily breakable 2.5mm. :stuck_out_tongue:

what does this cost? I can’t find any pricing online…

edit - nvm, $109 USD on their website.

It’s on amazon for $109 to avoid shipping costs

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how does it stack up to the competition?

does it have any feature or function that is it’s claim to fame? ie. ES100 has a 10 band EQ

Oh just gimme a minute. I’m doing a whole write-up with a side-by-side with the BTR5. And after talking with people who have both the Qudelix and the ES100, they basically concluded that the ES100 is completely outclassed by both this and the BTR5.


Hey all,

There does not seem to be much talk regarding the Qudelix-5k here, even though I’ve seen many hype it for the past year or so elsewhere because a former CTO of Radstone (of ES100 fame) decided to created this. And since I just got my BTR5 (Sky colored!), I thought a comparison was in order. I do not own an ES100, UP4, BTR3, BTR3k, or whatever else but from what I’ve been told both of these are improvements on the sound of those.

My audio source was my Samsung Galaxy S8 streaming music using Tidal Hifi over LDAC. I did not try to use them as USB DACs. Note I am still relatively new to this audiophile stuff. This is also a long post. Sorry not sorry.

FiiO BTR5 Qudelix-5K Both
Price FiiO BTR5 - $109.99 (Amazon). Comes in 3 colors but the Sky colored one is more expensive and has to be bought elsewhere. Qudelix-5K - $109.99 (Amazon) YMMV depending on where you order from.
Build Made in China. BTR5 has a glossy glass finish and sturdy metal exterior. It honestly feels like an Apple product. 4 buttons are all on one side and have icons printed beside them. It’s a fingerprint magnet. 45g so pretty weighty. Due to the weight I would not use as a dongle dac unless you strap it to something. Comes with removable plastic clip-on case that can be flipped if you need to flip it upside down for some reason. Has a built-in LED screen! For volume adjustment you have to press the volume buttons repeatedly. Holding the volume buttons up/down is last track/next track. The microphone hole is on the side right above the buttons. Made in Korea. Q5K has a matte plastic finish. Fingerprints show with oily fingers. 2 buttons are symmetrically on each side of the device and use red/blue LEDs that light up. You can change the LED behavior in the app. However, you kind of have to remember which side has the button that you want to press since there’s no icons. 25g so much more manageable as a dongle dac. Has a non-removable clip-on flap that is aluminum instead of plastic. You can hold down the volume buttons instead of pressing them repeatedly. IDK where the microphone is. Both use Type-C at the bottom for charging and use as a USB DAC. Both have 3.5mm and 2.5mm outputs at the top. This is notably different from the ES100.
Bluetooth + Range Supports aptX LL. Has an NFC reader. I got only got about 12 feet on LDAC before stuttering, but there are conflicting reports on the range so YMMV. But as it is now I feel tethered to my phone. Supports aptX Adaptive. I got a ridiculous 50 feet on LDAC before stuttering! Supports Bluetooth 5.0 with AAC, SBC, aptX, aptX HD, and LDAC
Battery Life I got around 7 hours. Takes around 1.5 hours to fully charge. I got around 4.5 hours using the more intensive performance mode + high output gain. Yes, I’m serious. WTF. Takes around 1.5 hours to fully charge. YMMV depending on your use.
Software Support BTR5 uses the FiiO music app. The app has it’s own music player that I would not bother with. Navigating the app is annoying and it seems to constantly run in the background. It also might be buggy or not work at all depending on what device you use (see Z review where FiiO DAP did not work). If your headphones/IEM have an inline microphone, you cannot use them. You have to use the mic on the BTR5. You get a 16 band EQ. This may change with a firmware update but as of right now, WHEN USING LDAC, YOU CANNOT ADJUST EQ. There are a handful of features in the app that you can play with, but I would honestly say you can use the BTR5 comfortably without the app. Q5K has its own Qudelix app. Navigation is much more intuitive. Since this is a new product, the app is actively being developed as well. There are options to use the inline mic on headphones/IEMs or use the mic in the Q5K. There are settings you definitely want to change within here like Standard vs Performance mode (aka gain switch). You get a 10 band EQ usable with LDAC. You immediately are logged for their 1 year warranty by connecting the Q5K to the app. Overall, in order to get the most out of your Q5K, the app is necessary but not confusing or intrusive. Both use mobile apps mainly to control the units. Both have volume control using sliders, Bluetooth codec control, battery life tracking, and PCM filter control.
Power Features a high/low gain you can toggle on the BTR5. Features a Normal/High output power gain but you can only toggle it in the app. I am tentatively going to say it has more power than the BTR5, though I do think it’s gear dependant. Both have very little noise floor.
Sound I really hope you didn’t just skip to this section. :cry: Simply put, the BTR5 is clean. Really clean. It’s more V-shaped than the Q5K. I find the detail retrieval and imaging superior to the Q5K. It’s hard for me to describe but all the music I play from this sounds fresh. The Qudelix has a little more color. I wouldn’t call it ‘warm’ but it’s certainly more mid-forward. I found instrument separation was superior and the soundstage was wider when compared to the BTR5. Only used as Bluetooth receivers using LDAC. YMMV otherwise.
Better Pairing Sennheiser HD650, BLON BL-03, Koss KPH30i Tin T2 Pro, Koss KSC75, Beyerdynamic DT880 600 ohm Sivga Phoenix

As for me personally, I like the sound of the BTR5 more thanks to that extra bit of treble, but I would take the Qudelix for almost any other reason. Especially since I can actually use EQ. That being said, I think the poor battery life of the Qudelix is a massive deal-breaker. I will definitely update this post in the future as I get more gear. But I’m not interested in buying more receivers for comparison because I’m already poor enough.

TLDR: Put your ES100 in the trash
BTR5 wins in build and battery life.
Qudelix-5K wins in power, bluetooth range, and software support.
Sound is gear dependant.

P.S. If FiiO ever releases a BTR5K the naming confusion would be awful lol


the battery issue may be why it never took off. seems they sacrificed battery to make it small and that was the wrong move to make.

Well that and nobody seems to be reviewing this thing. I’m sure Zeos will get to it once he’s done moving. Let’s see what he has to say about it.


Also pro tip: if you have a back posture corrector, consider doing this:

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He commented on the Qudelix forum while I was following it during development. I’d imagine he has one. Good little unit.

only 4.5 hours seems very awkward for using portably and the design of it is kinda bulky looking compared to the ES100 or the BTR5 due to its thickness… but the idea of a more warm sound and a much better app makes the very much a toss up… i just need to know which one will work better with the shozy 1.1s more V shaped and dynamic/fast/punchy sound

I’ll retest the Qudelix’s battery life and update accordingly. I only drained the battery all the way once using headphones (not IEMs) near max volume.

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That was on performance mode (better sq you probably only notice with high end iems and critical listening) and high gain (only necessary for power hungry loads - this thing drives Aryas! Lol). Neither are the default so I’m not sure how relevant this number is.

On the form factor: this thing is both thinner and narrower than the es100. It’s like half a mm taller. So I don’t know where you see the bulk :slight_smile:

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All right folks. Gonna do a battery stress test today. I also just did a firmware update (v1.3).

Qudelix-5k streaming Tidal Hifi at 20 feet away via LDAC, balanced 2.5mm out, high performance mode, high output gain, and max volume. Let’s see how long it lasts.

I might do a a similar test with the BTR5 later. See you in a few hours.


angry miniXLR 4-pin noises

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miniXLR is still too chonky man…

As long as I never take my ISN h40s out of my IEMatch or QP2R I shall never break the 2.5 lol

never say never, Felix. you just cursed yourself…Murphy now has his eye on you. :frowning:

That’s an oof

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The stress test is finished. The final time was 4 hours and 10 minutes. Obviously you can certainly prolong the battery life massively by doing things like using lower volumes, using low gain, using the 3.5mm out, not using LDAC, etc but this was a stress test so…