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Review: Apple vs Google USB-C Headphone Adapters

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amirm

amirm

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Would love to see a proper comparison round up of a few of these. There are quite a lot of options on Amazon.
I have been testing a lot of these. Search for "dongle" and you should find those reviews.
 

trl

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Not sure if anyone else posted before, so I found the below links containing nice pics about what's inside the Apple adapter:

https://www.ifixit.com/News/apple-audio-adapter-teardown

https://www.deccanchronicle.com/tec...it-inside-the-lightening-to-35mm-adapter.html

There's also an interesting test of more Apple audio dongles and "connectors" on https://www.heise.de/ct/artikel/iPh...apter-liefert-schlechteren-Sound-3325932.html, the table from in there where the iPad Air socket 106.7 dB (A-weighted) of dynamics for 24-bit audio files.

 

bobbooo

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Not sure if anyone else posted before, so I found the below links containing nice pics about what's inside the Apple adapter:

https://www.ifixit.com/News/apple-audio-adapter-teardown

https://www.deccanchronicle.com/tec...it-inside-the-lightening-to-35mm-adapter.html

There's also an interesting test of more Apple audio dongles and "connectors" on https://www.heise.de/ct/artikel/iPh...apter-liefert-schlechteren-Sound-3325932.html, the table from in there where the iPad Air socket 106.7 dB (A-weighted) of dynamics for 24-bit audio files.

As those last tests are by a German site, I presume it was the EU version of the lightning Apple dongle they were testing. That's if there are also two different versions, for the EU and US, like the USB-C dongle.
 
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Hi all,

I recently bought apple dongle. Which settings should I set in windows 10 for default format ? 16 or 24 bits ? 44 or 48 khz ? I know that if you're in direct mode it doesn't matter but it changes the sound if you're not (from my experience).

Ty
 

Veri

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Hi all,

I recently bought apple dongle. Which settings should I set in windows 10 for default format ? 16 or 24 bits ? 44 or 48 khz ? I know that if you're in direct mode it doesn't matter but it changes the sound if you're not (from my experience).

Ty
24-bit 44Khz seems best suited for general purpose.
 

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Another link for A2155 (EU). Max. 0.5v
https://reference-audio-analyzer.pro/en/report/amp/apple-usb-c.php

As another person asked earlier, how would this work out on Windows with Takstar Pro82 (max 1.3v RMS, 43mA, ~30 ohm, 96 dB/1mW )?

Point being that 2v RMS is where line level DACs should be. At half that output, it's a bit weak, but makes an acceptable headphone amp. At half that again are we in the territory of just not enough oomph except for really easy to drive earbuds and modern loudness war material?
 

trl

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Another link for A2155 (EU). Max. 0.5v
https://reference-audio-analyzer.pro/en/report/amp/apple-usb-c.php

As another person asked earlier, how would this work out on Windows with Takstar Pro82 (max 1.3v RMS, 43mA, ~30 ohm, 96 dB/1mW )?

Point being that 2v RMS is where line level DACs should be. At half that output, it's a bit weak, but makes an acceptable headphone amp. At half that again are we in the territory of just not enough oomph except for really easy to drive earbuds and modern loudness war material?

30_Ohms_THD.png

30.5 Ohms - Harmonics spectrum

30_Ohms_IMD_SMTP.png

30.5 Ohms - IMD SMTP

30_Ohms_IMD_CCIF.png

30.5 Ohms IMD CCIF

30_Ohms_Multitone.png

30.5 Ohms Multitone

Source: https://reference-audio-analyzer.pro/en/report/amp/apple-usb-c.php# (dBV -5.7V = 0.52V RMS)
 

L5730

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1576577607588.png

1576577645210.png

1576577809756.png


If I read the last chart correctly and apply P=IV and V=IR substitution P = V x V / R,
So ~3 mW = (300 mV x 300 mV) / 30 ohms. This is 10x less than what was measured from the other model on page 1 of this thread.

The top box I copied from that site says it all - too quiet.
 

maxxevv

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I read as 200mV at -115dB THD output to 30.5 Ohm from the chart you're sharing here though.

Max output ~550mV from your chart above.
P= VI , where I = V/R. => P = (V^2)/R. =>(0.55x 0.55 ) / 30.5 = 0.0099W => 10mW.

That is 10mW per channel if I read that correctly.
 

L5730

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^ thank you for the corrections and guidance.
The distortion jumps up fast after 300mV, so I took that rather than the max 0.5v output of the device.
Sure it can output 10mW max. into 30 ohm load, but if the distortion increases it's not useful. Saying that distortion is still under 0.001% or 105dB down.
 

maxxevv

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^ thank you for the corrections and guidance.
The distortion jumps up fast after 300mV, so I took that rather than the max 0.5v output of the device.
Sure it can output 10mW max. into 30 ohm load, but if the distortion increases it's not useful. Saying that distortion is still under 0.001% or 105dB down.
Its still a very good 0.001% on your chart.
And that 10mW is into 1 channel. Meaning its total output is 20mW.

Also, if you look at the table you shared above:


At 31 Ohm, max current before clipping is 0.01682 mA, at 550mV you do get an output of P=Vi => 0.00925W

Approx 9.25mW.

As for sufficient loudness or not, it depends on the headphone in question I guess.

In fact for relatively "not so easy" to drive headphones like the Hifiman / Massdrop HE4XX, the Apple dongle seems to have sufficient power.

Based on InnerFidelity's measurements, it only needs 1.51mW to reach 90dB SPL. It should be able to get close to 100dB SPL based on output values in your cited data.

https://www.innerfidelity.com/images/MassdropHiFiMANHE4XX.pdf
 

L5730

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Takstar Pro 82: Sensitivity rated ~96 dB SPL / 1mW. Too much power and the drivers will easily be damaged. So yeah, probably enough for these kinda cans. A low output impedance would be good to stop too much tonal change, which the dongle does.

OK, convinced. If my local store still has one I'll pick one up.

edit:
https://blog.jdslabs.com/2015/06/power-is-volume/
Judging by this info. With ~96 dB / 1mV sensitivity headphones, the EU Apple dongle should be capable of 110+ dB SPL at max.
 
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bobbooo

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View attachment 42808
30.5 Ohms - Harmonics spectrum

View attachment 42809
30.5 Ohms - IMD SMTP

View attachment 42805
30.5 Ohms IMD CCIF

View attachment 42807
30.5 Ohms Multitone

Source: https://reference-audio-analyzer.pro/en/report/amp/apple-usb-c.php# (dBV -5.7V = 0.52V RMS)
Looks like the first three are the wrong graphs - they're at a level of -12 to -14.7dBV, not the max -5.7dBV. I think this measurement at max volume would be a fairer visual comparison of the EU Apple dongle to the US version Amir measured:

Screenshot_2019-12-19 Measurement's report Apple A2155 USB-C to 3 5 mm Headphone Jack Adapter ...png



The US A2049 version Amir measured for comparison:

 

bobbooo

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I read as 200mV at -115dB THD output to 30.5 Ohm from the chart you're sharing here though.

Max output ~550mV from your chart above.
P= VI , where I = V/R. => P = (V^2)/R. =>(0.55x 0.55 ) / 30.5 = 0.0099W => 10mW.

That is 10mW per channel if I read that correctly.
You don't need to do any estimates or calculations, that page already lists the max power before clipping for various impedance loads:

Screenshot_2019-12-19 Measurement's report Apple A2155 USB-C to 3 5 mm Headphone Jack Adapter ...png


So that's a max power of 8.63 mW into a 31 ohm load before clipping, compared with the US version's 31 mW into 33 ohms as measured by Amir.
 

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Anyone have problems getting apple dongle to play at 44100hz under Linux? Using Ubuntu 18.04. I tried configuring PulseAudio every which way and it is refusing to work. avoid-resampling on, avoid-resampling off and both default and alternate rates set to 44100, returning config file to defaults, etc. the sample format (16 or 24 bit) does obey the config file, but sample rate stays at 48000 no matter what I do. Workaround is setting resampling algorithm to speex-float-10 to avoid quality loss, but this prevents me from multitasking since this uses quite a lot of cpu and starts stuttering if i do anything else.

I also tried running spotify without pulseaudio into alsa directly, but it does not appear to support this.
 
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This is interesting I started looking at max current and max peak current limits on iPhone and iPad with its dongle. Here is a table for a set of headsets, I started tracking to see how wild Impedance swings on headsets. I know I still need to add 75 & 85 dB normalization columns to look voltage and current.

I only started looking at this due to Dan Clarks Aeon X which I found a dramatic improvement with AMP even though it has a very low impedance. Also as a Scientist/Engineer, I want to know why.

On iPAD with Dongle, With headphones I own, I would say Focal Elex then the Hifiman Ananda, sound the best for a wide source of Audio material ( CD, Itunes, Youtube, etc), Note these both scale well with an amp. I find Hifman HE-4xx and Sennheiser HD 6xx are usable but very much improved with an amp. AEON X Open I would not recommend without and AMP

Screen Shot 2020-01-18 at 7.04.53 PM.png
 

ninetylol

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So whats the tldr of the EU version? I guess from what Im seeing here if volume is enough its just as good as US version? My headphones would be AKG K361.
 
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So whats the tldr of the EU version? I guess from what Im seeing here if volume is enough its just as good as US version? My headphones would be AKG K361.
Note you have a very sensitive headphone that will work fine. Also, you be operating at a much-reduced level of power/current then predicted here. 128 dB per 1 volt is extremely loud, aka deafening. Your headset is designed for working with mobile applications like iPhone, even Sony Walkman if you remember those.
Screen Shot 2020-01-22 at 8.52.07 AM.png

A Moderate speaking voice is around 70 dB

One thing I really like is on Headphone.com the main editor Torq when he review a headphone, he walk you thought what it takes to power it and also reminds us what is to loud for our hearing before damage.

1579705827126.png
 
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