Review: Apple vs Google USB-C Headphone Adapters

[3125b]

it's extremely likely you just had a ground loop

It's definitely an electrical potential related problem, but not a classic ground loop like that with active speakers for example.
The RME is an IEC Class II device with an external DC power supply. The problem occurs with USB devices and the mainboard audio (is that run via the USB controller?), however it is very variable in quantity. With the Topping E30 (DAC meant for desktop applications with seperate data and power lines) for example it makes about a 2dB difference from 110.x to 108.x, repeatable and definitely measurable, but that wouldn't constitute an audible concern. With the Apple dongle the effect is far, far greater.
With the dongle run from the laptop that is then plugged in via its power supply (also Class II), a 50Hz spike (and its second harmonic) becomes visible in the measurements, but the noise floor doesn't really change (and yes, I should use averaging to investigate such effects).
I suspect the dongle is just very sensitive to any supply voltage irregularities - don't let the snake oil brigade read that though
With the perfectly clean DC from a battery powered device - the way it was intended to be used - it just simply works best.

 

[edechamps]

The RME is an IEC Class II device with an external DC power supply.

In that kind of measurement setup the problem is not the AC mains, the problem is the USB ground. The ground loop is: Computer ground → USB Ground → DAC → Analog audio ground → ADC → USB Ground → Computer ground. The mains power supply is not involved (or barely). Breaking the USB ground using an isolator usually takes care of the issue.

 

[milw50717]

I built a little cased DAC box with RCA output around one of these dongles.

The main ingredients:

• 80 x 50 x 26 mm ABS project box
• 2 x RCA jacks
• USB-C coupler
• 1/8" TRS headphone plug

 

[Ismapics]

I built a little cased DAC box with RCA output around one of these dongles.

View attachment 127936

The main ingredients:

• 80 x 50 x 26 mm ABS project box
• 2 x RCA jacks
• USB-C coupler
• 1/8" TRS headphone plug

More pics pls. Like what you are doing here.

 

[milw50717]

More pics pls. Like what you are doing here.

The inside shot without the dongle is probably the most interesting as it show how things are wired and epoxied together. I wanted the ability to remove the dongle and using the layout shown below allows it to be easily fitted and sit with a natural curve in the short wire lead.

Here is my first attempt, with the TRS by the RCAs. I didn't like the angle at which the dongle wires sit, so I switched to the above configuration

 

[Ismapics]

QUOTE="milw50717, post: 785274, member: 5869"]The inside shot without the dongle is probably the most interesting as it show how things are wired and epoxied together. I wanted the ability to remove the dongle and using the layout shown below allows it to be easily fitted and sit with a natural curve in the short wire lead.


View attachment 130319View attachment 130320View attachment 130321View attachment 130322View attachment 130323

Here is my first attempt, with the TRS by the RCAs. I didn't like the angle at which the dongle wires sit, so I switched to the above configuration

View attachment 130326[/QUOTE]

Thanks for sharing. It looks really cool. A couple questions. When I use mine, the Mac Mini does not detect it unless there are headphones plugged in. In your case, is it detected as its stands or does it need loads on the RCA? Finally, there are more than $10 in additional parts right? But still the time tinkering and the final product is really cool.

 

[milw50717]

It is detected on my Mac Mini M1 as a 'USB-C to 3.5mm Headphone Jack Adapter' with nothing attached to the RCAs.

If you had to buy all the parts then the price is going to be over $10. Here are my costs - 5 x cases for $8, 5 x TRS plugs for $1.50, 2 x USB-C couplers for $4 and I had the RCAs and wire in my spares box.

 

[appleboy11]

do u people think it's audio output better than typical android phone in the market?
I've tin t2 plus been using my phone {samsung m31} for driving them should i buy this.
Ps I just want to know whether aplle type one will increase soundstage or clarity etc do let me know with ur experience..

 

[roflcopter]

Can this be used for a DAC into a home theater receiver/ amp?

I'm looking to set up a few squeezelite clients for a multiroom audio setup. I'd like to avoid spending a $100 DAC on each one. (In Australia they're more like $150-200 for a basic one)

It'd be feeding into a Yamaha RX-V685 (into the analog RCA inputs via a 3.5mm to RCA adapter)

Not sure if these headphone adapters cause any voltage or double-amping issues compared to a straight DAC that has line-out?

 

[Ralph_Cramden]

The Apple USB-C dongle I bought from Amazon appears to convert everything to 48K. No 44.1 support. The stream is 44.1K, but playback shows 48K, and only 48/16 and 48/24 are supported. Other $10 dongles I have, on the same Pi host, support up to 384K (though perhaps noisier/more distorted, though I haven't noticed such).

/proc/asound/card0$ cat stream0
Apple, Inc. USB-C to 3.5mm Headphone Jack A at usb-20980000.usb-1, full speed : USB Audio

Playback:
Status: Running
Interface = 1
Altset = 1
Packet Size = 288
Momentary freq = 48000 Hz (0x30.0000)
Interface 1
Altset 1
Format: S24_3LE
Channels: 2
Endpoint: 2 OUT (SYNC)
Rates: 48000 - 48000 (continuous)
Bits: 0
Interface 1
Altset 2
Format: S16_LE
Channels: 2
Endpoint: 2 OUT (SYNC)
Rates: 48000 - 48000 (continuous)
Bits: 0

 

[LYDF]

Living in EU I got one just to have a cheap DAC to go with a pair of 560S and yes, it does lower the sound (many records from the 70s I like are just loud enough).
If I were an avid jazz-classical music listener, I'd probably feel the need to get an amp.

On a sidenote, should I notice an evident difference with/without it? I have it plugged to my desktop pc but I didn't really.

 

[Veri]

Living in EU I got one just to have a cheap DAC to go with a pair of 560S and yes, it does lower the sound (many records from the 70s I like are just loud enough).
If I were an avid jazz-classical music listener, I'd probably feel the need to get an amp.

On a sidenote, should I notice an evident difference with/without it? I have it plugged to my desktop pc but I didn't really.

All depends on the desktop but yeah maybe not really.

 

[LYDF]

All depends on the desktop but yeah maybe not really.

If you are interested ,the motherboard is this one, Realtek® ALC892/ALC897 Codec.

Right now the only reason I find the dongle handy is so that I can have plugged in on the back both headphones and speakers...but maybe that's something achievable with a normal splitter as well?

 

[Veri]

If you are interested ,the motherboard is this one, Realtek® ALC892/ALC897 Codec.

Right now the only reason I find the dongle handy is so that I can have plugged in on the back both headphones and speakers...but maybe that's something achievable with a normal splitter as well?

The dongle might in fact simply be better than that now rather dated ALC solution.

 

[LYDF]

The dongle might in fact simply be better than that now rather dated ALC solution.

In that case, I'll keep it. It looks so fragile though, and I don't have a proper way to shrink wrap it.

 

[Veri]

In that case, I'll keep it. It looks so fragile though, and I don't have a proper way to shrink wrap it.

Right it does look fragile but mine all still work. Depends on how bad you treat it hehe. I think I've seen some smart ways of wrapping it on reddit IIRC to make it a little more robust

 

[LYDF]

Right it does look fragile but mine all still work. Depends on how bad you treat it hehe. I think I've seen some smart ways of wrapping it on reddit IIRC to make it a little more robust

I'm just scared of the overall weight and strain it has to support plus the 90° angling.
I've googled but I can't find anything related to reinforcing it, do you have any link?

 

[Veri]

I'm just scared of the overall weight and strain it has to support plus the 90° angling.
I've googled but I can't find anything related to reinforcing it, do you have any link?

I looked and looked but can't find it back =( sorry.

 

[wizzie]

has anyone measured their A2155 (EU version)?
0.5vrms is fine for my IEM's but is the EU version worse than the US version when it comes to audio quality?
(on windows)

 

[Billy Budapest]

The inside shot without the dongle is probably the most interesting as it show how things are wired and epoxied together. I wanted the ability to remove the dongle and using the layout shown below allows it to be easily fitted and sit with a natural curve in the short wire lead.


View attachment 130319View attachment 130320View attachment 130321View attachment 130322View attachment 130323

Here is my first attempt, with the TRS by the RCAs. I didn't like the angle at which the dongle wires sit, so I switched to the above configuration

View attachment 130326

Cool idea, but why not cut off the TRS and strip the cable and connect it directly to the RCA jacks?