Qudelix-5K Bluetooth DAC & Headphone Amp

[amirm]

LDAC better than USB, very interesting,

It is not. See above. The USB tests were run at high sample rates since that is all it exposes by default. Once I got them down to the same 44.1 kHz, as you see above USB improves.

 

[PeteL]

Sure. Here you go:

View attachment 92888

Strange thing is that if I change the sample rate above 48 kHz (e.g. 96 kHz), it reproduces the above tone at 500 Hz instead of 1000! Maybe this is the reason by default they don't enable other sample rates.

I don't know about this chip, I don't recognise the number, probably new, but the CSR8675 Qualcomm Flagship SOC up till a couple year is USB audio Class 1, it does weird stuff, and it's not even an asynchronous transfer which is the main perk of USB audio class 2.

 

[Cahudson42]

Very nice to be listening to Masaaki Suzuki Bach Organ Works without any distortion at all (HE400i balanced, Oratory1990 PEQ)

Unless it's all those harmonics giving me that great $10k Pass Labs signature...

Edit: Source - $30 LG Rebel TracFone Android 8, USB OTG, Amazon music HD App. WiFi.

 

[Veri]

Very nice to be listening to Masaaki Suzuki Bach Organ Works without any distortion at all (HE400i balanced, Oratory1990 PEQ)

Nice set-up

 

[AlexScan]

It is not. See above. The USB tests were run at high sample rates since that is all it exposes by default. Once I got them down to the same 44.1 kHz, as you see above USB improves.

Thank Amir to take the measurement at 44.1khz, so the Quedelix work better at 44.1khz, and performance was the same USB or LDAC.

According to Head-Fi reviewer he listen virtualy no difference between USB or LDAC:

The fundamental conclusion is that there are hardly any differences between the two sources.

https://www.head-fi.org/showcase/qudelix-5k.24672/


Another thing Amir, can you measure power versus distorsion in Normal mode and 2.5mm output under 33ohm load ? (LDAC or USB at 44.1Khz)

 

[PeteL]

Thank Amir to take the measurement at 44.1khz, so the Quedelix work better at 44.1khz, and performance was the same USB or LDAC.

According to Head-Fi reviewer he listen virtualy no difference between USB or LDAC:


https://www.head-fi.org/showcase/qudelix-5k.24672/


Another thing Amir, can you measure LDAC and USB at 44.1Khz in Normal mode and 2.5mm output ?

@amirm as we are in special requests... If possible, I'd like a measurment for a 16 bit file for AptX... I got much better than this when measured AptX HD, Unfortunately I didn't ever checked AptX but AptX HD is a good CODEC. When I was switching to AptX listening to 24 bit encoded music, there was a clear audible degradation. I was under the impression that AptX was just a 16 bit version of AptX HD 24 bit CODEC. Also, at the time I was measuring from the Audio Precision Bluetooth module for APx555. I seam to see that you don't have a AptX HD source right? If you do I'd like to know if those oddities remain, maybe the source, not sure, those AptX measurment are bothersome to me, especially since LDAC do so well, but I can't demonstrate this.

 

[bobbooo]

I don't know about this chip, I don't recognise the number, probably new, but the CSR8675 Qualcomm Flagship SOC up till a couple year is USB audio Class 1, it does weird stuff, and it's not even an asynchronous transfer which is the main perk of USB audio class 2.

From here, it seems the Qualcomm QCC5124 SOC the Qudelix 5K uses includes two DACs (a class D and a class AB - possibly the former is used in the app's 'standard' mode and the latter in the 'performance' mode?). Both go up to 192kHz sample rates (although Qudelix apparently limits this to 96kHz), so I believe that suggests it's not USB audio class 1 but class 2:

The full datasheet also mentions a UART (universal asynchronous receiver transmitter) interface. The Qudelix website says the USB DAC is "USB Audio Class 1.0 / No additional driver needed" though, so maybe that's also a limitation they've imposed for greater compatibility?

EDIT: Some or all of what I wrote above may be incorrect

Looks like the THD+N measured in this review unit is right on spec comparing the above numbers with the updated measurements here using the correct sample rate setting (as suspected it seems like source device upsampling was the culprit for the original lower SINAD over USB). It is a bit of a waste of the brilliantly performing dual ES9218P Sabre DACs the Qudelix has though to be bottlenecked by the lower performing QCC5124, but really, the 5K's measured harmonic distortion components below -90dB will still be an inaudible addition to the playback chain anyway, and could even enable it to be used as a cheap, audibly transparent parametric speaker/room EQ device feeding a stereo amp/receiver or AVR. Quite the versatile little thing. (I'm now wondering if it would be possible to somehow Frankenstein the Qudelix onto an AVR to get the latter's own output as well as input to go through the 5K...) Talking of PEQ, I think it would be interesting to see if enabling this (and so the QCC5124's embedded dual 32-bit Kalimba DSP cores) on the Qudelix has any affect on SINAD (with all EQ filters and preamp gain set to 0dB of course), as this is the device's killer feature really that differentiates it from the competition and will be enabled during playback for many users.

 

[Asylum Seeker]

Fiio BTR5, pleasseee...

 

[amirm]

Another thing Amir, can you measure power versus distorsion in Normal mode and 2.5mm output under 33ohm load ? (LDAC or USB at 44.1Khz)

I currently don't have a balanced 33 ohm load so can't do that. I think you can safely interpolate from the 50 ohm load that it can produce a ton more power in balanced.

 

[PeteL]

From here, it seems the Qualcomm QCC5124 SOC the Qudelix 5K uses includes two DACs (a class D and a class AB - possibly the former is used in the app's 'standard' mode and the latter in the 'performance' mode?). Both go up to 192kHz sample rates (although Qudelix apparently limits this to 96kHz), so I believe that suggests it's not USB audio class 1 but class 2:

View attachment 92895

View attachment 92896

The full datasheet also mentions a UART (universal asynchronous receiver transmitter) interface. The Qudelix website says the USB DAC is "USB Audio Class 1.0 / No additional driver needed" though, so maybe that's also a limitation they've imposed for greater compatibility?

Looks like the THD+N measured in this review unit is right on spec comparing the above numbers with the updated measurements here using the correct sample rate setting (as suspected it seems like source device upsampling was the culprit for the original lower SINAD over USB). It is a bit of a waste of the brilliantly performing dual ES9218P Sabre DACs the Qudelix has though to be bottlenecked by the lower performing QCC5124, but really, the 5K's measured harmonic distortion components below -90dB will be an inaudible addition to the playback chain anyway, and could even enable it to be used as a cheap, audibly transparent parametric speaker/room EQ device feeding a stereo amp/receiver or AVR. Quite the versatile little thing. (I'm now wondering if it would be possible to somehow Frankenstein the Qudelix onto an AVR to get the latter's own output as well as input to go through the 5K...) Talking of PEQ, I think it would be interesting to see if enabling this (and so the QCC5124's embedded dual 32-bit Kalimba DSP cores) on the Qudelix has any affect on SINAD (with all EQ filters and preamp gain set to 0dB of course), as this is the device's killer feature really that differentiates it from the competition and so will be enabled during playback for many users.

Thanks for this. I would need to see the full datasheet, but may I.. Don’t know how to say this in a diplomatic way, but I have to give my insight because, Some of those statement would confuse people. the thing is, none of those audio output are used if it has ess dacs for conversion. it’s the digital interface we have to look at, not the « audio output ». We also have more than 30 mW in 32 ohms, so they do not use the amp section neither, if such a thing make sense with the conversion being done by an external dac chip. the fact that this can do 192 khz, it’s great we would need to see the use case for this, it doesn’t give us info on the usb receiver tough. UART is a control interface. It doesn’t say anything about audio. That said, don’t feel bad about this those are not stupid misunderstanding. It’s not fair, I did a very similar project. Before even to start behing productive, it’s not unusual to take a full week to understand datasheets.

 

[bobbooo]

Thanks for this. I would need to see the full datasheet, but may I.. Don’t know how to say this in a diplomatic way, but I have to give my insight because, Some of those statement would confuse people. the thing is, none of those audio output are used if it has ess dacs for conversion. it’s the digital interface we have to look at, not the « audio output ». We also have more than 30 mW in 32 ohms, so they do not use the amp section neither, if such a thing make sense with the conversion being done by an external dac chip. the fact that this can do 192 khz, it’s great we would need to see the use case for this, it doesn’t give us info on the usb receiver tough. UART is a control interface. It doesn’t say anything about audio. That said, don’t feel bad about this those are not stupid misunderstanding. It’s not fair, I did a very similar project. Before even to start behing productive, it’s not unusual to take a full week to understand datasheets.

Yeah I only took a quick look at the datasheet late at night. I was thinking the Qudelix 5K might be 'double amping' with the QCC5124 and the ES9218P. I linked to the full datasheet in my previous post (within the 'From here' of the first sentence), but here is the link again. Please feel free to correct any (or all) of what I said

 

[wslee]

Yeah I only took a quick look at the datasheet late at night. I was thinking the Qudelix 5K might be 'double amping' with the QCC5124 and the ES9218P. I linked to the full datasheet in my previous post (within the 'From here' of the first sentence), but here is the link again. Please feel free to correct any (or all) of what I said

There's no such an application in the market.
ES9218p is a DAC/AMP, which menas D/A converter with integrated HPAMP.
ES9218p receives the digital audio through I2S interface.

 

[Haint]

I bought one of these as a universal solution to apply the Harman and Oratory PEQ to all my headphones with almost any source. It works very well for that purpose. @amirm do you suggest setting the USB DAC to 44.1 or 48Hz for best performance?

 

[wslee]

Sure. Here you go:
Strange thing is that if I change the sample rate above 48 kHz (e.g. 96 kHz), it reproduces the above tone at 500 Hz instead of 1000! Maybe this is the reason by default they don't enable other sample rates.

I'm not so sure if I'm allowed to write a post here.

But, you need to check the 5K USB FS setting first.
Unlike other USB DAC, 5K USB DAC offers an option to change the device supported sample rate.
Please go to the app INPUT --> USB, and check the device supported sample rate.

In the beginning, 5K delivers its supported sample rates to the USB HOST, and the USB HOST selects one of them.

Thanks!

 

[Cahudson42]

Hopefully, the Qudelix 5k shows the future of $100-$200 Desktop DAC/Amps. Topping, Schitt, JDS, SMSL, Geshelli et al only need to provide PEQ, reconstruction filter selection, balanced/unbalanced, sample rate selection, digital volume control, etc. and Android/IOS Apps to control via simultaneous bt.

Do this while retaining their current 110-120 SINADs and 1 watt plus outputs, and they will have obsoleted their current products and created a nice new market for themselves...

Perhaps it will also provide a wake-up call to miniDSP to finally provide Android/IOS Apps for their devices as well. Their continuing to require a PC to off-line download control parameters reeks obsolescence, and leaves them wide open for a new competitor in their DSP space..

 

[mSpot]

I'm not so sure if I'm allowed to write a post here.

Welcome, and nice to see you here! I suggest that you send a message to @amirm and ask if there are rules you need to follow as manufacturer.

 

[amirm]

I bought one of these as a universal solution to apply the Harman and Oratory PEQ to all my headphones with almost any source. It works very well for that purpose. @amirm do you suggest setting the USB DAC to 44.1 or 48Hz for best performance?

Definitely 44.1 kHz to match the content you play.

 

[amirm]

But, you need to check the 5K USB FS setting first.
Unlike other USB DAC, 5K USB DAC offers an option to change the device supported sample rate.
Please go to the app INPUT --> USB, and check the device supported sample rate.

??? That is how I changed the sample rate for that test. Without that change, you are stuck at the high 96 kHz sample rate. I don't know why you are explaining to me.

 

[wslee]

??? That is how I changed the sample rate for that test. Without that change, you are stuck at the high 96 kHz sample rate. I don't know why you are explaining to me.

Apologize if I bothered you.
I thought you have the ownership for the test.

At first, I appreciate the lovely review and kind comments.
I'm WS from Qudelix, Inc.

"Strange thing is that if I change the sample rate above 48 kHz (e.g. 96 kHz), it reproduces the above tone at 500 Hz instead of 1000! Maybe this is the reason by default they don't enable other sample rates."

I just want to let you know that the above might be the environmental issue or a setting issue.
As you may know,
USB DAC sends its capability and HW spec, including bit precision and sample rates, to the connected USB HOST PC at the beginning.
Then, the host PC selects one of them when playing/streaming audio over USB.

5K supports 44/48/88/96KHz FS.
In that mode, you can select one of them on the PC.

Also, 5K can opt-out and limit the supported sample rates at one specific fs.
For example, when connected to an Android device, we can't select the FS unless we use the UAPP app.
In that case, we can opt-out of the sample rates by limiting the 5K DAC FS capability.

So, for the test with Windows PC, you may need to select 44/48/88/96KHz Full Fs mode via the app.

As we tested, 5K USB DAC offers the same performance within an acceptable margin across the sample rate.

Thank you once again for the review.
Please remove my post if I'm not allowed to write here as a manufacturer.

Have a good day!
WS

 

[amirm]

Please remove my post if I'm not allowed to write here as a manufacturer.

You are very welcome to post as a manufacturer. We much appreciate it!