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Dec 22, 20228 min read

How to Compare USB-C Dongles

Updated: May 13, 2023

Do you have a phone that doesn't have 3.5mm audio jack? Are you in the market for a USB-C audio DAC/Amp dongle for headphones, IEMs, or earbuds? With so many dongles to choose from, how can we make sense of the performance and value?


First of all, This blog post is on audiophile USB-C dongles that provides DAC chip used, features, and power. And DAC chips have public datasheets with performance data. These dongles have higher PCM sampling rate and power output. And most support DSD. Some even support MQA.


This blog is not on the cheap < $10 dongles, such those from Apple, Google, Samsung, or various Amazon models. Those cheap dongles likely use Conexant chip. There are no specs provided; sampling rate limited to 44.1 kHz. I have Apple lightning and USB-C dongle; Stouchi from Amazon. Apple does not specify the DAC chip. Stouchi states Conexant. I can easily hear a difference in these dongles vs audiophile dongles or desktop DAC/Amps. Lacks bass; vocals are lean; trebles are muted (less open and less airy).

Then 1 tier up from that are $15-$20 dongles that uses Realtek DACs. Examples are Moondrop Click, Avani, Xumee, ZOOAUX, etc. They are available either on Amazon or AliExpress. Some are 24bit/96kHz; some are 32bit/384kHz. Besides that, there is not much info. Sometimes they specify the Realtek DAC chip model; other times they do not. And Realtek does not publish its datasheet online, so no way to compare performance data of these DAC chips. I did not do much research beyond this, because there is no data or info available. And I have no experience with these, so I won't be able to say if these are bad, sufficient, good, etc. So not included in this blog.


Compare DAC Chip

USB-C dongle has both DAC and Amp. The DAC converts the digital signal from the source (such as phone, notebook, or computer) to analog. The Amplifier then add gain to sound volume in order reach the desired listening volume. First on the DAC:


When I was doing comparison shopping, I noticed the DAC chips used are quite standard. There are around 10 DAC chips that are commonly used in dongles. Each DAC chip has different specification, performance, and market tier. There is correlation between dongle price and DAC chip used. So basically, these dongle makers select the DAC chip with appropriate price and feature based on target market tier. So if you compare the DAC chip, that will give you an idea on the tier and pricing.


DAC chips are typically from ESS Technology, AKM, or Cirrus Logic. Right now, the market is dominated by ESS Tech. There was a fire at one of AKM's semiconductor factory in 2020. Since then, AKM DAC chips are in short supply. I suspect that did restrict dongle makers from going with AKM chips, but I don't know the exact impact.


Here is a list of popular dongles that I saw in my comparison shopping. I grouped them by DAC chip used. Plus current prices (as of December 2022). Then further down on this page, I captured the various DAC chips' specs (sampling rate, SNR/DNR/THD, etc) in tables.


Dongles with ES9038Q2M chip:

Dongles with ES9219 chip:

Dongles with ES9218 chip:

Dongles with ES9281 chip:

Dongles with AKM chips:

Dongles with Cirrus Logic CS43131 chip:

This list can provide quick idea on which dongles to further focus on for more reviews, versus which expensive outliers to avoid.


ES9038Q2M has slightly better measurements (DNR 128 dB, THD 120 dB). It is used by higher tier dongles models, around $100. Fiio KA3 and Shanglin UA2 are good value with lowest prices using this DAC chip. Based on this comparison, I purchased Fiio KA3 on sale at $75.


Fiio Jade Audio KA3 ($90) - Check prices on Amazon


ES9219, ES9218, and ES9281 have slightly worse measurements (DNR 121-122 dB, THD 106-114 dB). These are used mainly in $40-$60 dongles. Dongles using AKM AK4377 and Cirrus Logic CS43131 are also in this similar pricing tier.


There are outliers due to other features, such bluetooth wireless feature in Qudelix-5K and Fiio BTR5. The additional bluetooth chips and added battery will cost extra; thus increasing the cost on those models.


Then there are some dongles that have pricing structures that just do not quite make sense. With prices that are 2-3x more than other dongles using the same DAC chip. If they have additional killer features, then I can accept that. However, I don't see those killer features to justify the cost.


Amplification Power

After you identified the tier based on DAC chip. Next step is to double check the power output specification. Unfortunately, amplifiers are not standard. Some use off-the-shelf IC amplifiers (such as Op Amps); others use their own amplifier design. Power specification does matter. Higher power is better, even if you don't need it. It gives you more headroom and options to upgrade in future. If everything is equal, get the higher power. But if you don't need the power, no need to pay extra for that.


Typically, for desktop and headphones (particularly hard to drive or high impedance ones), we need to look at complete power specs for various impedances. That will ensure there is enough power, plus headroom, for your particular headphones. However, for dongles, manufacturers often do not provide the complete power spec. They typically just list the max power (which is usually at 16 or 32 ohm impedance). The power can drop off significantly at higher impedances (300 ohm or larger).


I suspect the reason is that USB-C dongles are catered toward mobile/portable market. So most people will be using dongles with their IEMs and mass market headphones. These devices typically have high sensitivity, low impedances, and are not hard to drive. So for most folks, just a single power number is sufficient to do your comparison shopping.


However, if you have harder to drive headphones (such as lower sensitivity planar magnetic headphones) or high impedances headphones (such as Sennheiser HD600/650/6XX with 300 ohm impedance), then you need to check reviews that the dongles of interest can effectively drive your headphones.


Design and Features

On the design side, the most important factor for me is the cable. I would look at the cable whether it is detachable or not. I believe it is safer to get a DAC with detachable USB cable. If the cable is damaged, I can replace it. Or if I plan to use the DAC with desktop PC, I can get a longer cable.


On features, check if these matter to you:

  • Android vs IOS support: some dongles have settings (gain, PCM filters, L/R balance) that requires app to access

  • 4.4mm balanced output

  • LED status lights

  • Volume control

  • Microphone support

  • Bluetooth receiver

Dongle Pairing with Headphones/IEMs

Lastly, you want to check the reviews on sound quality and pairing. This last part is more qualitative than quantitative. The best resource I found for dongle review is Andy Audio Vault #donglemaddness. Check link at very bottom of this page.


Then it is even harder if you want to know how the dongle pairs with your headphones or IEMs. You have to search on reddit or forums for owners having that exact pairing, and someone who has listened to various setups to provide relative comparisons.


DAC Chip Specs

Below is specification for various DAC chips. These numbers are all from publicly available data sheet. Again, mostly from ESS Technology as they just have a lot more DAC chips out there, for both desktop and dongles. Below that are small tables for AKM and Cirrus Logic.


ESS Tech PRO 8-channel: More for desktop, rather than dongle. Just including the data here for completeness. I gathered this data when I was shopping for desktop DACs.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9039PRO

8

32

768

1024

Y

132

122

ES9038PRO

8

32

768

256

​

132

122

ES9028PRO

8

32

768

256

​

129

120

ES9027PRO

8

32

768

1024

Y

124

114

ES9026PRO

8

32

768

256

​

124

110

ESS Tech 8-channel: Again, for desktop, rather than dongle.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9018

8

32

384

64


129

120

ES9017

8

32

768

512

​

120

110

ES9080

8

32

768

512

​

120

108

9006A

8

24

196

64

​

120

102

ESS Tech Audiophile 2-channel: Again, mainly for desktop.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9068AS

2

32

384

1024

Y

126~130

120

ES9033Q

2

32

768

512

​

122

108

ES9023P

2

24

?

?

​

112

?

ESS Tech 2-channel: Here, we start to see dongle usage.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9038Q2M

2

32

768

512

​

128

120

ES9028C2M

2

32

384

512

​

129

120

ES9028Q2M

2

32

384

512

​

129

120

ES9018C2M

2

32

384

256

​

127

120

ES9018K2M

2

32

384

256

​

127

120

ES9016K2M

2

32

384

256

​

122

110

ES9010K2M

2

32

384

256

​

116

106

ESS Tech SOC: SOC has volume control support. See quite a bit of dongle usage here. Some dongles do utilize the volume control. Other dongles use these SOC DAC chips with the capability, but do not implement physical volume buttons.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9219MQ/Q

2

32

384

256

Y

121

106-114

ES9218PQ

2

32

384

256

​

121

106-114

ES9118EQ/EC

2

32

384

256

​

120

105-112

ESS Tech USB: These support mic function, but it depends whether the dongle maker implemented that.

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

ES9281A Pro

2

32

384

1024

Y

122

110-112

ES9280A Pro

2

32

384

1024

​

122

110-112

ES9270C

2

32

384

-

​

117

108-112

ES9260Q

2

32

384

256

​

118

101-106

AKM

​

Ch

Bit Rate

PCM

DSD

MQA

SNR (dB)

THD (dB)

AK4377

2

32

768

256

​

128

106-109

AK4375A

2

32

192

-

​

110

?

Cirrus Logic

​

Ch

Bit Rate

PCM

DSD

MQA

DNR (dB)

THD (dB)

CS43198

2

32

384

256

​

130

115

CS43131

2

32

384

256

​

130

115

CS41918

2

32

384

256

​

130

115

What do these number mean?

  • Channel: 2 channel is default, for Left and Right. The higher-end chips (for desktop) can have more than 2 channels.

  • Bit Rate: 32-bit is quite standard, so there is not much to compare here. This bit rate determines the number level available to the digital-to-analog decoder. 32-bit means there are 2^32 = 4,294,967,296 discrete levels, which translates to 193 dB SNR (signal-to-noise ratio). There is no way to utilize this. So it is more marketing pitch than anything. And I cannot hear any difference between 16 vs 24 vs 32-bit.

  • PCM: This is the standard encoding/decoding method, using Pulse Code Modulation. The number is the sampling rate. You can decide how high of sampling rate you require. Based on Nyquist Theorem, 40 kHz sampling rate is needed to decode 20 kHz frequency. I read that covers 1st order harmonics; higher order harmonics require higher sampling rate. And I do hear a slight difference between 44.1 vs 192 kHz. With higher sampling rate, I hear the treble as more open and airy. Above 192 kHz, I cannot hear any difference.

  • DSD: This is Direct Stream Digital that uses Pulse Density Modulation for encode/decoding, which is single-bit encoding at high sampling rate. Useful (or must have) if you have files encoded in this format.

  • MQA: This is Master Quality Authenticated. This enables hi-res audio streaming. I believe only Tidal Premium offers MQA currently. Note that some DAC chips have MQA option. For instance, ES9219Q is non-MQA version; ES9219MQ has MQA support. So definitely check the dongle spec, instead of DAC spec, for MQA support.

  • SNR (dB) and DNR (dB):

    • ESS Tech is not consistent in its datasheet. All of them includes DNR (dynamic range), but only selected few provides SNR (signal-to-noise ratio). So I only included the DNR numbers for ESS Tech.

    • I believe it is fair to compare noise numbers between ESS Tech chips, but not when compare # between these 3 companies.

    • Higher number is better. But it is all relative. For instance, no one can say if SNR/DNR needs to be certain value to produce good audio. SNR/DNR can be measured, but it is beyond human hearing to notice differences at these levels. Here is my take. If you are paying the same price and if everything else is equal, get the product with higher DNR or SNR. On the other hand, I would not pay extra for dongles with DACs have couple dB higher DNR/SNR. You should rely on other features (e.g. price, power, sound, etc) to make your decision.

  • THD (dB): Total harmonic distortion in decibels. Typically, THD is presented as %, where lower is better. When THD is converted to decibel scale, then higher number is better. Again, similar to DNR/SNR. Numbers at this level can be measured, but our hearing cannot difference a few dB differences. If everything else is same, go with the product with lower THD % or higher THD in dB.

Links

Here are some websites and forums for additional information:



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