Qudelix-5K Bluetooth DAC & Headphone Amp

[Acerun]

The former should work. You can check if it does by making sure the sample rate in the Qudelix app under Input > State matches the sample rate of your input device / track. If it doesn't, just change it to that specific sample rate in the Qudelix app.



Yes. Although you only 'need' to make this adjustment if there isn't enough volume for you with the EQ profile's default preamp.

Sorry, I'm confused with this last sentence. Do you input the EQ profile as is or do you do the math to change the EQ profile preamp setting, taking -6db into consideration as the baseline?

 

[Acerun]

The former should work. You can check if it does by making sure the sample rate in the Qudelix app under Input > State matches the sample rate of your input device / track. If it doesn't, just change it to that specific sample rate in the Qudelix app.

Hmm... Doesn't look like the sample rate shows in the Amazon HD app for Android. Does anyone know how to enable it/find it? It shows when I use Amazon HD on Firestick. There's a setting to display it.

 

[jhaider]

Is it possible to do so? I do not think that the 5K can be used as a « DAC only » device. Can it be confirmed by a current 5K user?

Yes, it works. I've found the output was not sufficient to allow a HeadRoom Desktop Amp to satisfactorily drive Sennheiser HD580. I don't know what the amp's input sensitivity is; others may have lower input sensitivity and in that case it's a no-brainer. For my specific application I've found a miniDSP 2x4HD does have enough voltage output for the amp to drive HD580 to well beyond any levels I'd want to use.

 

[bobbooo]

Sorry, I'm confused with this last sentence. Do you input the EQ profile as is or do you do the math to change the EQ profile preamp setting, taking -6db into consideration as the baseline?

Personally I just input the EQ profile as is, then only if I need more volume adjust the EQ preamp taking into consideration the -6 dB Qudelix preamp ('headroom'). You can do the latter every time if you want, up to you.

Hmm... Doesn't look like the sample rate shows in the Amazon HD app for Android. Does anyone know how to enable it/find it? It shows when I use Amazon HD on Firestick. There's a setting to display it.

Depending on your Android device, it's likely going though the Android audio mixer and resampling to 48 kHz anyway, so whatever the Amazon Music HD app might report probably won't be accurate. Just set the Qudelix to 44.1/48/88.2/96 kHz and see what's selected by checking Input > State > Sample Rate in the Qudelix app while playing a track from Amazon Music.

 

[Acerun]

Personally I just input the EQ profile as is, then only if I need more volume adjust the EQ preamp taking into consideration the -6 dB Qudelix preamp ('headroom'). You can do the latter every time if you want, up to you.



Depending on your Android device, it's likely going though the Android audio mixer and resampling to 48 kHz anyway, so whatever the Amazon Music HD app might report probably won't be accurate. Just set the Qudelix to 44.1/48/88.2/96 kHz and see what's selected by checking Input > State > Sample Rate in the Qudelix app while playing a track from Amazon Music.

Thank you. The good news is that it says that it's playing almost everything off Amazon HD at Sony LDAP 24/96 990 something bitrate. At least I think that's good.. it sounds really good.

 

[bobbooo]

Thank you. The good news is that it says that it's playing almost everything off Amazon HD at Sony LDAP 24/96 990 something bitrate. At least I think that's good.. it sounds really good.

Oh...you're using the Bluetooth connection. I was talking about the USB connection. The selectable 44.1/48/88.2/96 kHz etc. sample rate settings are only for USB connections, not applicable to Bluetooth. After all they're under Input > USB > USB DAC FS in the Qudelix app.

 

[Acerun]

Oh...you're using the Bluetooth connection. I was talking about the USB connection. The selectable 44.1/48/88.2/96 kHz etc. sample rate settings are only for USB connections, not applicable to Bluetooth. After all they're under Input > USB > USB DAC FS in the Qudelix app.

Yes the Bluetooth is way more convenient. If I do plug it in I just was thinking about what I should have it set at.

 

[ehabheikal]

Need to review the not so new fiio btr5 as a direct competitor.

My sentiments exactly

 

[ehabheikal]

One greet capability of the Qudelix-5K is its bluetooth reception range (in LDAC). I find it has about twice the range of the Fiio BTR5 receiving from the same transmitter. The Qudelix will work across a garage full of metal shelving and metal items while the Fiio isn't even close.

Can you tell them apart sonically? i am thinking of which one gets better sound

 

[rcmo]

I could not, at all. Ended up selling the Fiio.

 

[Acerun]

I posted this on the Qudelix forum, don't know if any of you know the answers as well.

If I'm streaming a track whose quality is 16-bit/44.1KHz it looks like my Samsung phone may be upsampling to the Qudelix max rate because it "sees" the Qudelix can handle 24-bit/96 KHz/990. Does that sound right?

Follow up to that, if I change my settings in my Samsung to 16-bit/44.1KHz output I see that the Qudelix shows play at 44.1KHz. Will this be higher quality than the "upsampled" 24-bit/96KHz?

Third observation. Even though my Samsung output is set at 16-bit/44.1 KHz, Qudelix shows it is playing at 44.1KHz/24-bit/909. Why does it show 24-bit when my phone is set to send 16-bit? Also, when an "Ultra HD" song comes on, the Qudelix shows the same play rate of 44.1KHz 24-bit but Amazon Music HD shows "currently playing" at 44.1 KHz/24-bit and on some tracks 48KHz/24-bit.

 

[Acerun]

I posted this on the Qudelix forum, don't know if any of you know the answers as well.

If I'm streaming a track whose quality is 16-bit/44.1KHz it looks like my Samsung phone may be upsampling to the Qudelix max rate because it "sees" the Qudelix can handle 24-bit/96 KHz/990. Does that sound right?

Follow up to that, if I change my settings in my Samsung to 16-bit/44.1KHz output I see that the Qudelix shows play at 44.1KHz. Will this be higher quality than the "upsampled" 24-bit/96KHz?

Third observation. Even though my Samsung output is set at 16-bit/44.1 KHz, Qudelix shows it is playing at 44.1KHz/24-bit/909. Why does it show 24-bit when my phone is set to send 16-bit? Also, when an "Ultra HD" song comes on, the Qudelix shows the same play rate of 44.1KHz 24-bit but Amazon Music HD shows "currently playing" at 44.1 KHz/24-bit and on some tracks 48KHz/24-bit.

And the response from Qudelix:

Good question.
Bluetooth A2DP, every track is transcoded through a designated audio codec for transmission over Bluetooth.
For a 16-bit/44.1KHz source, the OS oversamples it to 96KHz and encoded it LDAC 96KHz. As we researched, the limited LDAC bitrate is wasted for the meaningless oversampled frequency region.
Thus, for any 44KHz source track, setting LDAC frequency the same as the source track, i.e. 44.1KHz, would provide the optimal sound quality since every LDAC bits are fully used for the active frequency band.

And 16-bit would be encoded with 8-bit or 16-bit zero paddings, depending on the bit resolution settings. Practically, LDAC 24 or 32 bit would provide the same sound quality. For 16-bit source track, those zero-padding would help to keep the resolution even at low source digital volume control. However, 5K provides 2-way associative absolute volume control, and the audio is always encoded at full precision.

Our recommendation for the optimal LDAC performance is that:

• set LDAC frequency the same as the source track
• set the bit resolution 32

Thanks~!

 

[Acerun]

I'm not an expert in these things yet, but perhaps I can offer a useful opinion in the meantime.

I really, really like how the Qudelix handles volume controls.

The first thing to keep in mind is that volume levels in the digital domain do not need to change the audio signal at all. Some devices (e.g., Android) will digitally compress the signal so that the amp can maintain a constant amount of gain, but that's not the norm. The USB/UAC spec provides coding for metadata about the desired volume level so that the sound samples always remain full scale but the amp can modify analog gain out of the DAC appropriately. (I do not know about Bluetooth, but I would be surprised if it isn't the same.) So, you can run the computer audio out at 100% or 10% (unless it is Android, but I think you're using Windows) without running into problems. [This contrasts with sending an analog signal out to the amplifier, in which case noise remains constant but reducing volume reduces signal, reducing the signal:noise ratio.]

Qudelix does something I haven't seen before, though I doubt it is unique to hifi. It has two volume controls: one reflecting the requested volume level from the OS, and another set within the Qudelix. The fantastic thing about this is that you can set the Qudelix to play the highest desired gain when the OS setting is at 100%. I like to listen quietly to IEMs, so I'm rarely going above 25% on most OS controls; with the Qudelix, that level of gain becomes 100%, so I have the full scale at my disposal for fine tuning. If I want even finer tuning, the Qudelix adjusts at 0.5dB increments. I have never before been able to achieve exactly the volume level that I want, every single time.

(Additionally, you can set the Qudelix's internal volume range, but that's not likely relevant in this context.)

This is independent of setting the gain to normal (1V max) or high (2V max), which I guess gives you another degree of control.

Another thing: the Qudelix presents a fine-grained volume control to the OS. I don't know why, but most devices I've used have jumped volume levels in large chunks, like they only have 16 levels available or something. The built-in device usually has fine control; my Apple dongle offers fine control; my Qudelix also offers fine control. As it should be.

All that is to say: I don't think you'll have any problem setting the Qudelix to push the exact voltage range you desire to the JDS Atom.

The final kicker, for me, is that these settings are easy to adjust. Easy enough that it is no headache to set up custom limits and EQ for one pair of headphones, then swap those settings out for another pair. All of the gain levels are marked numerically, so they're easy to return to. I've used other BLE devices that hang for a few seconds while updating settings. The Qudelix app does not hang while communicating with the device, and the changes occur within a small fraction of a second, maybe 200ms typical. So I have no problem imagining a workflow where you plug it into your desktop kit with one group of settings for your workday and then unplug it, change the settings for a set of headphones that's good for choring while listening over Bluetooth, then change the settings later for another set of headphones that's good for dedicated listening, movie watching, gaming, isolating yourself from everyone around you, or whatever other goals you have. All the while providing you exactly the sound quality you want in each context. All while being forward compatible with balanced equipment yet the box is smaller than an XLR connector. Nuts.

The Qudelix isn't perfect, but I am incredibly impressed at how well it does what it set out to do, not to mention how much the firmware has continued to improve since release less than a year ago. If you're willing to tweak a few settings -- which I suspect you are, given that you were looking for PEQ options -- then I think you'll be quite pleased, as I am.

Any reason I couldn't use the Qudelix as a PEQ DAC into the JDS Element II? If I understand correctly, It's being used in that capacity currently with the Atom. Could I use the Element as just an amp to keep the PEQ from the Qudelix?

 

[Cahudson42]

Qudelix has released a new version v1.7.0 including a form of crossfeed:
https://www.qudelix.com/pages/forum

Not much info, except it's billed as 'stereo speaker emulation' with a slider controlling the percentage of mix. No details on timing delays or variations in amplitudes with frequency etc..

 

[rcmo]

I didn't spend enough time on it yet. IMO, crossfeed is something that you need to turn on and be able to forget it is there to evaluate whether it feels good or not. I'll try to do so on and off with RME's.

Nevertheless, I really appreciate how qudelix listens to the users and their approach to a UI that would otherwise (traditionally) be a mess.

 

[Acerun]

Qudelix has released a new version v1.7.0 including a form of crossfeed:
https://www.qudelix.com/pages/forum

Not much info, except it's billed as 'stereo speaker emulation' with a slider controlling the percentage of mix. No details on timing delays or variations in amplitudes with frequency etc..

My app hasn't auto updated to 1.7.0. Are you manually updating your app?

 

[Cahudson42]

Are you manually updating your app

I'm waiting until it appears in Google Play, as installing from Qudelix Forum link means I need to uninstall current version first and lose all entered PEQs.

Definitely will be interesting to see how new crossfeed behaves. This, to me, was the one missing feature provided by the RME ADI-2. With it, imo the Qudelix can now be considered a 'poor man's RME', even for prime desktop use.

Even though the power output is still less, another $100 solves that with a Heresy or whatever follow on amp.

And even though Amir dissed it's DAC, noise is low, and THD is still 90db down.
I can't hear any difference with my LG V20 Quad DAC, with it's much better DAC measurements.

So for a little over $200, there is now an RME ADI-2 alternative.

 

[Acerun]

I'm waiting until it appears in Google Play, as installing from Qudelix Forum link means I need to uninstall current version first and lose all entered PEQs.

Definitely will be interesting to see how new crossfeed behaves. This, to me, was the one missing feature provided by the RME ADI-2. With it, imo the Qudelix can now be considered a 'poor man's RME', even for prime desktop use.

Even though the power output is still less, another $100 solves that with a Heresy or whatever follow on amp.

And even though Amir dissed it's DAC, noise is low, and THD is still 90db down.
I can't hear any difference with my LG V20 Quad DAC, with it's much better DAC measurements.

So for a little over $200, there is now an RME ADI-2 alternative.

I'm still new to DACs, but the Qudelix has opened a whole new world for me. I just got a HE4XX and a Meze balanced cable. Popped in the updated Oratory PEQ settings and I can play as loud as I should on the Qudelix with performance/normal power settings... And it sounds amazing. It does seem like the sound quality degrades a bit on high power setting.

 

[Acerun]

You could also think of it as a mobile RME not just a poor man's RME. I'm seriously rethinking whether I even need a headphone amp.

 

[brian_h_kim]

I'm waiting until it appears in Google Play, as installing from Qudelix Forum link means I need to uninstall current version first and lose all entered PEQs.

the PEQs are stored on the device - not the app