- Connecting audio
- Audio PC
- Raspberry & Co
- All in Ones
- Bluetooth
- Chromecast
- Streaming audio player
- Music server
- USB Audio
- Real-time audio over IP
- FireWire DAC
- Multi-channel DAC
- NAS
- Remote control
- Vinyl rippers
- Acoustic materials
- Active crossover
- Active speakers
- Single driver speakers
- Invisible speakers
- Sound card
- Digital room correction
- Headphone
- Portable media players
USB-C
More and more manufacturers of mobile phones drop the 3.5 headphone jack.
Indeed, without this jack it is easier to make the mobile waterproof.
Another trend is replacing the micro USB connector with a USB-C connector.
Today you can get dongles with USB-C in and 3.5 analog out.
This means there is a DAC build-in.
However, there is also a USB-C Audio Adapter Accessory Mode.
In this mode the device sends analog audio over the USB.
All you need is a passive adapter.
Obvious, USB-C is the most analog sounding digital bus!
To the best of my knowledge, there is nothing you can do as a user to invoke Audio Adapter Accessory Mode or avoid it. But is might explain why a passive USB-C - headphone adapter works or fails to work because you need an active one.
A bit more about USB and this Audio Adapter Accessory Mode can be found here.
Allo audio Pilot $129.00
ESS Sabre DAC (9281CPRO with MQA support)
SNR: 120db
THD+N @ 0.0006%
< 2 ohm output impedance
PCM sampling frequency up to 384kHz
DSD sampling frequency up to 5.6MHz
Earmen Donald DAC $99
PCM 384kHz/32bit,
DXD, MQA Rendering
DAC: 32 bit Cirrus Logic CS 43198
USB: XMos 2XX
Input: USB-C - DATA/Power Supply
USB-C - External Power Supply
Output: RCA
Dimensions: L * H * W (mm) 114 x 80 x59
Meaurements on 
Google USB-C to 3.5 mm headphone adapter US$12
Is this a passive or a active adaptor?
CableDo did a teardown.
Indeed, there is a DAC inside.
Microsoft Surface USB-C to 3.5 mm adapter $11.99
Looks like a passive but thanks to CableDo we know there is a DAC inside.
Musiland MU1 US $38.50
Supports 16 or 24Bit, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz full sample rate audio format playback.
Headphone output power up to 2x60mw/32 ohms, can drive up to 120 ohms headphones, output up to 300mA transient current.
Intelligent suitable for output impedance, support line output whose impedance above 600ohms; output level IV RMS
Zorloo Ztella
ESS Sabre DAC technology
SNR @ 120dB
THD+N @ 0.0006%
< 2 ohm output impedance
PCM sampling frequency up to 384kHz
DSD sampling frequency up to 5.6MHz
References
- 3.5mm audio vs USB Type-C: the good, bad and the future - Robert Triggs
- USB-IF Publishes Audio over USB Type-C Specifications - Anton Shilov 2016
- Headphone dongles - ASR
- Apple vs Google USB-C Headphone Adapters -