Review: Apple vs Google USB-C Headphone Adapters

[Nutul]

...or if there is a risk of damaging the headphones by not using powerful enough amp? Thanks!

I still fall short of understanding how could you possibly damage something not being strong enough to even drive it properly...
Maybe with 4 Ohm IEMs you could burn the dongle... or drain your phone's battery so fast you'd set it on fire...
I stand free to be contradicted, though, as it is indeed an interesting topic, especially for what concerns really-low impedence loads.

 

[Baneat]

This is a review, detailed measurements and comparison of Apple's USB-C adapter to the current and last version of Google Pixel headphone adapters. The Apple adapter costs just $9 including one day shipping for free. The Google dongle costs $12.

Not that any of these are large by any stretch but Apple's is also the smallest of the three:

View attachment 18460​

Oddly there is no apple logo or markings on the device. The others don't have it either but I thought Apple would insist on that.

All three adapters work in Windows with the appropriate adapter and that is how I tested them, allowing my analyzer to fully control and quantify their performance.

Format wise, Apple's supports the key ones:
View attachment 18461

So very similar to Google Pixel V2 and better than V1 which only supported 48 kHz.

Note that volume control in Windows is active at all times even if you use WASAPI exclusive mode!

Not much else to talk about than getting into measurements.

Measurements
As always, let's start with our dashboard view at maximum volume:
View attachment 18462

Oh wow! That is good. Very good for a dongle. Here is how the SINAD compares:

View attachment 18463

As you see, it leaves both Google dongles in the dust. Mind you, built-in DAC in LG G7 ThinQ is much better still so Android fans don't need to kill themselves. Clearly someone cared about audio performance here in design of Apple dongle.

Let's look at jitter:
View attachment 18464

That's massively lower noise floor and distortion spikes than the Google pixel V2.

Seeing how this is a semi-serious DAC performance, I thought I run some adult tests on it like Linearity:
View attachment 18465

Most excellent again for something that is tinier than your fingernails!

Here is Dynamic Range:

View attachment 18498

The most important metric for these is how much power they have. There was some criticism of my Google Pixel measurements so I decided to remeasure them and refine the graphs and setting. While Google Pixel V2 repeated its past performance, the V1 produced less power. I don't know what is up with that. But here is the data anyway:

View attachment 18467

The Apple USB-C headphone dongle betters both in noise. It then proceeds to produce much more power than Google Pixel V2 and a bit more than V1.

Here are the results for much more stressful 33 ohm load:
View attachment 18468

Here the noise performance is similar but the Apple Dongle has a commanding lead over both Google dongles with respect to power.

Putting these in a graph we get this (sorted by 300 ohm power):
View attachment 18469

As we see, the Apple USB-C adapter even beats the small thumb drive sized Audirect Beam!

Story doesn't end here. Let's look at the output impedance:
View attachment 18470

At 0.9 ohm, the Apple USB-C dongle has near ideal output impedance whereas Google V2 is far higher at 7.6 ohm.

Listening Tests
I started my listening tests with my AKG K92 headphones. Here, there was ample power with excellent fidelity when using the Apple headphone adapter. Hard to imagine this much oomph coming out of such a tiny thing. The extra power was very audible as compared to Google V1 and V2. I am listening to the Apple dongle as I am typing this, having to keep the Windows volume control at just 18 out of 100 on my headphone electronic music.

Switching to high-impedance 300 ohm Sennheiser HD-650 nearly killed performance. The sound was OK but bass is week and dynamic range just not there. Here my reference is more powerful desktop and battery operated portables.

Finally I tested the Hifiman HE-400i. This wasn't nearly as loud and dynamic as AKG K92 but still quite good!

Bottom line: if you have a lower impedance headphone or an efficient one, there is no reason to apologize for using the Apple headphone adapter.

Conclusions
It is time for us Android users to crawl under a rock. Apple showed us that a bit more thought and engineering put in a dirt cheap and small audio product can produce respectable performance. The objective performance gap with Google dongles especially with their regression to version 2 is vast. This is both on objective front and subjective listening tests.

Note that my testing is all on Windows. I attempted to test on my Samsung S8+ and got odd results. Using both Google dongles, all they did was route the not so good sound of the internal DAC through the dongle (???). With Apple dongle I got music but level was very low. So if you plan to use the Apple dongle on an Android phone, you should do some compatibility testing.

FYI I have two other dongles to test in the future. For now, I can recommend the Apple USB-C headphone adapter. For many people it may replace the portable thumb drive dac+amps.

Now please forgive me as I go drown out my sorrows as an ex-Microsoft guy having to recommend an Apple product....

-------------

As always, questions, comments, recommendations, etc. are welcome.

If you like this review, please consider donating funds to support these reviews using either:
Patreon (https://www.patreon.com/audiosciencereview), or,
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).

Concerning higher impedance headphones such as the hd650 - can someone explain to me what is meant by “killing performance” from this dac/amp? I noticed Amir mentioned something similar in the review for the hd650s themselves - a similar statement that these headphones “like” a 2Vrms + source. Is the effect being described measured, particularly comments regarding bass?

I have the EU dongle and it gets just loud enough at 90% ish volume with the 650s (and I do mean just - I would not be able to apply much negative gain for eq headroom or listen to extremely low level tracks without adding gain in a different way other than the volume slider) for my purposes - my understanding was that as long as it can provide ample voltage and supply enough current for the levels you listen at there’s no difference between “transparent” amps.

The impedance of the 650s climbs to 500 ohms at 100Hz and the only thing I have really done is check what loudness one can expect from the dongle at that impedance using an online tool ([email protected]). Are the described issues of dynamic range and bass response removed if the volume is set to e.g. 50%? In which case if you are also adding an amp in-line can your issue be resolved by setting the dongle to e.g. 20% and adding the gain through the dedicated amp?

I’m not that really well informed on audio and there does appear to be a lot of misinformation surrounding dacs and amps in the broader internet discourse - but this sort of thing regarding this dongles limitations seems like something one could measure or explain in terms of physics. I’ve seen a fair few recommendations of this dongle for hd650/6xx/600, particularly the US variant on the basis that it’s loud enough for music at high volume levels, so something clear and concrete on why it’s not a good idea I think would be helpful to others as well.

P.s. can anyone with both variants of this dongle say what the equivalent volume for 100% on EU is for US on the volume slider?

 

[staticV3]

Concerning higher impedance headphones such as the hd650 - can someone explain to me what is meant by “killing performance” from this dac/amp? I noticed Amir mentioned something similar in the review for the hd650s themselves - a similar statement that these headphones “like” a 2Vrms + source. Is the effect being described measured, particularly comments regarding bass?

It's just volume.
The Apple dongle cannot output high voltages and so the headphone cannot output high SPLs.
There is no effect on just the bass.

Any description thereof is the result of equal loudness contours (louder music sounds more V-shaped, despite equal frequency response)

P.s. can anyone with both variants of this dongle say what the equivalent volume for 100% on EU is for US on the volume slider?

The EU version has 6dB lower max output than the US version.
You can apply a 6dB reduction in Equalizer APO, Audacity, Foobar, etc.

 

[Baneat]

It's just volume.
The Apple dongle cannot output high voltages and so the headphone cannot output high SPLs.
There is no effect on just the bass.

Any description thereof is simply caused by equal loudness contours.

Switching to high-impedance 300 ohm Sennheiser HD-650 nearly killed performance. The sound was OK but bass is weak and dynamic range just not there. Here my reference is more powerful desktop and battery operated portables.

I failed to correctly quote the relevant section of the OP and its long enough my context wasn’t clear - this is the paragraph I meant. Do you simply disagree with the above paragraph? What you’re saying is what I thought just from a physics perspective but this isn’t the first time I’ve read observations in this vein on this forum - I’m wondering if I’m missing part of the picture

 

[staticV3]

Do you simply disagree with the above paragraph?

I don't. The Apple dongle has limited output capabilities, so cannot play very loud depending on what headphone you use.

A quiet headphone will sound un-dynamic and Ʌ-shaped (missing bass and treble). This is entirely caused by psychoacoustics and is not an inherent, measurable attribute of the electronics.

 

[Baneat]

I don't. The Apple dongle has limited output capabilities, co cannot play very loud depending on what headphone you use.

A quiet headphone will sound un-dynamic and Ʌ-shaped (missing bass and treble). This is entirely caused by psychoacoustics and is not an inherent, measurable attribute of the electronics.

I was operating off the assumption that the listener would level match the two setups to the limit of the lower of the two (if it’s not loud enough at 100%) and just comment that it doesn’t get loud enough but sounds the same as the other setup at the same level if it’s all explainable by perception of volume.

 

[staticV3]

I was operating off the assumption that the listener would level match the two setups to the limit of the lower of the two (if it’s not loud enough at 100%) and just comment that it doesn’t get loud enough but sounds the same as the other setup at the same level if it’s all explainable by perception of volume.

I don't think that's what happened.

In the listening test, Amir simply pushes the DUT to its limit and reports back what he hears. Controls like blind testing and level matching are not part of his procedure afaik.

 

[Baneat]

I don't think that's what happened.

In the listening test, Amir simply pushes the DUT to its limit and reports back what he hears. Controls like blind testing and level matching are not part of his procedure afaik.

Thank you - I will take the measurements for what they are and conclude as well as I can from that alone, then. Which is to say that if 100% is starting to get uncomfortably loud with the 650s for me on the EU dongle then it’s perfectly fine to use it at 90% without concerns that it’s messing with dynamics or response.

Re. 6dB it’s what I thought since the voltage is halved - but I can’t find anything that explains how the iPhone expresses its volume slider in terms of output - closest thing I could find suggests the US version has about 2 clicks above the EU 100%

 

[staticV3]

Thank you - I will take the measurements for what they are and conclude as well as I can from that alone, then. Which is to say that if 100% is starting to get uncomfortably loud with the 650s for me on the EU dongle then it’s perfectly fine to use it at 90% without concerns that it’s messing with dynamics or response.

Re. 6dB it’s what I thought since the voltage is halved - but I can’t find anything that explains how the iPhone expresses its volume slider in terms of output - closest thing I could find suggests the US version has about 2 clicks above the EU 100%

I only have the Type-C versions, but could test it on an iPad if you'd like

 

[Jimbob54]

I don't think that's what happened.

In the listening test, Amir simply pushes the DUT to its limit and reports back what he hears. Controls like blind testing and level matching are not part of his procedure afaik.

Its the earlobe vibration test protocol - if the amp can get the headphones to make em wiggle without obvious distortion it bodes well for either the amp or headphones depending on what is the DUT. Highly scientific test, that! ;-)

 

[DSJR]

With the cheapo in-ears I often use (aids removed), the US spec Apple dongle is usable at 14 - 20 out of 100 scale on this Windows laptop (USB A - C adaptor in series).

 

[staticV3]

I only have the Type-C versions, but could test it on an iPad if you'd like

@Baneat
So it turns out that both the iPad Air 5th gen (17.1.1) and the iMac 27" Late 2012 (10.15.7) can disable the EU Voltage limit of the A2155 Apple dongle, and so I got the same volume with both versions (A2049 and A2155), on those two devices.

Whether you may get that 0.5V limit on your Apple device, I can't tell.
All Windows, Linux, and Android devices will encounter the EU limit on EU dongles, afaik.

I highly recommend you get a basic multimeter though, with which you can measure output voltages yourself.
This can be extremely helpful when troubleshooting audio equipment.

 

[somebodyelse]

I don't suppose you can capture whatever they're sending to it to to that? It might be possible to add it to the linux driver or mixer quirks.

 

[staticV3]

I don't suppose you can capture whatever they're sending to it to to that? It might be possible to add it to the linux driver or mixer quirks.

Is there an inexpensive device that would allow me to capture this? I guess I'd need a logic analyzer?

 

[somebodyelse]

Maybe wireshark on the Mac? I know it works on linux. It's meant to work on Windows, but I couldn't get it working on a VM running Windows with the USB port passed through, so I captured it on the linux host OS instead. That was to see what the windows driver was doing with a Focusrite Forte.

 

[IndieSynth]

Help! I just purchased the apple dongle for my android phone. I knew of the issues and was expecting low volume, so i also purchased USB Audio Pro. I've set hardware volume to max over the app but get a horribly distorted sound when I then start to play music on Spotify. It's louder, but it's really glitchy. What am I doing wrong?

 

[staticV3]

Help! I just purchased the apple dongle for my android phone. I knew of the issues and was expecting low volume, so i also purchased USB Audio Pro. I've set hardware volume to max over the app but get a horribly distorted sound when I then start to play music on Spotify. It's louder, but it's really glitchy. What am I doing wrong?

I just double-cheched on my Tab S5e and Oneplus 6T with both versions (A2049 and A2155). Couldn't replicate the issue.

Two questions:
After launching UAPP and setting Hardware volume to Max, do you close UAPP properly with the side bar menu->Exit?


Afterwards, when playing music on Spotify, how loud do you put the regular Android volume?

 

[IndieSynth]

Thanks staticV3. I followed that process and same issue happened, then I wiggled the usb in and out, it asked me the 'hand over control to the app' question, I clicked cancel and now it's working perfectly at decent volume!

Update - this is bizarre, it's really hard to recreate, it needs a very slight wiggle but doesn't work if actually removed. I guess the dongle is faulty. Unless I do the exact sequence including slight wiggle I get either very low volume or high volume but continuous 'b b b b b' distortion.

 

[Emlin]

Thanks staticV3. I followed that process and same issue happened, then I wiggled the usb in and out, it asked me the 'hand over control to the app' question, I clicked cancel and now it's working perfectly at decent volume!

Update - this is bizarre, it's really hard to recreate, it needs a very slight wiggle but doesn't work if actually removed. I guess the dongle is faulty. Unless I do the exact sequence including slight wiggle I get either very low volume or high volume but continuous 'b b b b b' distortion.

Same here, so I don't think it's your dongle. Very disappointing.

What's the next best measurements wise?

 

[staticV3]

What's the next best measurements wise?

You can search for cs43131 on Amazon/eBay/AliExpress and get one of those dongles (JCally JM20, MB21P, etc).

Those measure better than the Apple dongle, however, not all of them have a microphone imput and they draw about 3x as much current from your phone as the Apple dongle.