Earstudio HUD100 Portable Headphone DAC & Amp Review

[amirm]

This is a review and detailed measurements of the Earstudio HUD100 Portable USB-C DAC and Headphone Amplifier. It was sent to me by the company for review. I can't find a price or availability for HUD100 in US first. I read some place it may cost US $100. In that regard, it competes with likes of AudioQuest Dragonfly products (which have not done well in my tests). Unlike previous offers from Earstudio, the HUD100 is just a DAC and Amp with no Bluetooth or battery inside.

Despite being small, the HUD100 manages to look classy in its small but cute looking aluminum case:

On one side there is a USB-C connector and a momentary switch that forces a firmware upgrade:

On the other side you have a low and high power headphone output the latter of which more than doubles the output voltage for high impedance headphones. The slide switch is three-way with bypass (the way I tested it) and two other processing mode. In my quick test I did not find the effect audible on the one track in either setting.

Sadly there is no volume control on the unit.

Included in the package are a short and longer USB-C cables that are some of the best I have seen. They have a soft and supple feel.

Unlike many dongles, compatibility with Windows PC where I tested it was good in that the ASIO interface does not truncate to 16 bits. On the other hand, I could not get it working from the USB hub in my monitor which I use for many DAC tests. The native USB port on my desktop worked however.

DAC Audio Measurements
Let's treat the unit as a DAC by not loading it with low impedance load as we would test a DAC:

Distortion and noise is respectable for a dongle but well short of company spec. There is that rise in noise in low frequencies which may be system dependent and would explain why they would get better numbers with another source. Lowering the input by 1 dB to get 2 volt nominal improved performance by 1 dB. So as it is, there is no record broken:

EDIT: I had test the above using the Dynamic mode. Here are the updates in bypass (effect) mode:

But there is excellent data in our dashboard in the form of 2.2 volt output. 1 volt is the common output level for dongles which means there won't be much power available for high impedance headphones (power = voltage * voltage /impedance). Better ones have 2 volts out and here we have 2.2 which is even nicer. Importantly this is in "unbalanced" output so no need to get a balanced cable to get more output.

Signal to noise ratio is not exceptional due to noise issue we have seen already:

EDIT: Bypass mode is 1 dB better.

Intermodulation noise and distortion is very good for dongle:

A "MEMS" oscillator is used to drive the DAC instead of a clock oscillator. Here is our jitter test:

We clearly have data dependent jitter (not caused by the clock) but levels are below audibility so not a concern at all. The output is also far cleaner than dongles which due to lack of filtering, usually have a ton of noise and spurious tones in this test.

Linearity was surprisingly good:

This test filters out noise so shows the underlying accuracy of the DAC.

Multitone results are also encouraging for this class product:

All of the above measurements are appetizers for the main meal of power testing:

As we see here, we have the same power in unbalanced mode with HUD100 than we did with ES100 in balanced:

Output impedance was comfortably low:

Headphone Amplifier Listening Tests
I started testing with my Sennheiser HD-650 high impedance headpohne. There was plenty of power here with average listening test requiring a volume of 50 out of 100. At full volume, there was no distortion that I could detect and plenty of detail and punch bass (see? I can write flowery subjective reviews!). Switching to the Hifiman HE400i which has a low impedance but efficient and experience was the same (very good).

I then tried my Ether CX 25 low, super low efficient headphone on the HUD100. Here, there was decent volume until you turned it up more and sound clearly got distorted in a nasty way. Still, at lower volumes it was listenable. So no miracle or serious competition to desktop DACs.

Conclusions
The level of performance Earstudio HUD100 provides should be standard in computers and portable phones and tablets. Alas, it is not. The price may be high but the HUD100 fixes these deficiencies in an attractive package with nice accessories.

I am happy to add the Earstudio HUD100 to my recommended list.

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

Someone wrote to me complaining about me "begging" for money from you all after spending so much on expensive measurement gear. As if I could be shamed that easily. So please donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[Cahudson42]

Am I correct, the Apple A2049 adapter @ $9, combined with the NX3s (provided you have Planar or other fr constant impedanceHP) @ $70 - $79 total, outperforms this both SINAD and power?

 

[Veri]

So far this is only sold in Korea, priced at over $150.

It is also on drop just now. $149 pre-order price. https://drop.com/buy/radsone-hud100-dac-amp

 

[MZKM]

So far this is only sold in Korea, priced at over $150.

It is also on drop just now. $149 pre-order price. https://drop.com/buy/radsone-hud100-dac-amp

I would have assumed the decently better performance but with no Bluetooth and no app with adjustable DSP would have balanced out price-wise.

 

[ZolaIII]

For what exactly did this got recommendation? I don't understand? SINAD is bad it has a bit more power but still not to consider it as serious, it doesn't have volume control & it's plagued with USB power delivery issues. For the half price there are far better one's.

 

[Matias]

Agree this is not particular good measuring, Hidizs S8 is similar priced and a lot better performance. Let alone Tempotec Sonata HD Pro for less.

 

[ZolaIII]

Agree this is not particular good measuring, Hidizs S8 is similar priced and a lot better performance. Let alone Tempotec Sonata HD Pro for less.

Add & Meizu Pro to the list & even E1DA is cheaper and better & more serious. Sonata HD Pro & NX3S combined cost less & burn the house down on this.

 

[amirm]

For what exactly did this got recommendation? I don't understand? SINAD is bad it has a bit more power but still not to consider it as serious, it doesn't have volume control & it's plagued with USB power delivery issues. For the half price there are far better one's.

What?

 

[bobbooo]

Thanks for the review. The Quedlix 5K, made by the developer of the Earstudio ES100 after he left Radsone to form his own company, looks to be a much better proposition than this HUD100. It uses dual ES9218P DACs (the same as in the lauded LG smartphones) with up to 4V output (balanced, 2V unbalanced), has optional Bluetooth (aptX Adaptive, LDAC, AAC, aptX-HD), a max 21-hour battery life, and a 20-band parametric hardware equalizer for system-wide EQ, with an app to easily adjust this. It's also $99 to the HUD100's $150. Should be out by the end of the month if you want to test it.

The level of performance Earstudio HUD100 provides should be standard in computers and portable phones and tablets. Alas, it is not.

Apart from max volume, which isn't that important to the majority of people who use these products with IEMs and reasonably sensitive portable headphones not at deafening levels, what objective evidence is there that the average modern smartphone doesn't achieve similar levels of performance within audibility to products like these?

 

[ZolaIII]

What?

Should that impress me? Nx4 is above with deacent SINAD costing 159$ - 152 with discount. Sound BlasterX & E1DA 3038S eat it alive and Sonata HD Pro + NX3S go even future all for less than 150$.

Guess you warent joking about subjective review.

 

[MZKM]

Should that impress me? Nx4 is above with deacent SINAD costing 159$ - 152 with discount. Sound BlasterX & E1DA 3038S eat it alive and Sonata HD Pro + NX3S go even future all for less than 150$.

Guess you warent joking about subjective review.

There is a massive size/weight difference. Vastly more people would be inclined to commute with this rather than a Nx4.

 

[amirm]

Should that impress me? Nx4 is above with deacent SINAD costing 159$ - 152 with discount. Sound BlasterX & E1DA 3038S eat it alive and Sonata HD Pro + NX3S go even future all for less than 150$.

Yes, it should impress you very much. It is easy to get high power with an internal battery which with it brings longivity issues, and heavy weight and size.

E1DA gets is power with balanced connection. I was clear about the benefit and cost savings of not having to mess with that with this device.

Guess you warent joking about subjective review.

Darn right. I pay particular attention to whether there is sufficient power to drive audiophile headphones. If you only care about tiny amount of power, sure, there are other products that have my recommendation as well. This one, is able to power standard and very popular headphones to high SPLs, resulting in good bass performance. I am not wasting my time with subjective tests with no value.

 

[amirm]

Apart from max volume, which isn't that important to the majority of people who use these products with IEMs and reasonably sensitive portable headphones not at deafening levels, what objective evidence is there that the average modern smartphone doesn't achieve similar levels of performance within audibility to products like these?

That's like saying apart from handling, what value is there in a porsche. Power is everything in tiny DAC and Amps. It is absolutely audible when these little devices run out of juice and distort heavily. Or cut out. This is a special class of device where power is compromised first and foremost. Look at Google dongle for example.

It seems that some of you are not familiar with the target market and application for these devices.

And remember, I did not give it my highest marks. It simply performs well enough all around for me to recommend it.

 

[Xulonn]

At full volume, there was no distortion that I could detect and plenty of detail and punch bass (see? I can write flowery subjective reviews!).

Sorry Amir, you forgot to post the "punchiness" graph. /snark

 

[ZolaIII]

Sorry it just performs bad (under 16 bits) & everything else is less relevant. Audiophile headaphones is very stretched statement for me that certainly ain't those with bass bost.

 

[bobbooo]

That's like saying apart from handling, what value is there in a porsche. Power is everything in tiny DAC and Amps.

You're like the Jeremy Clarkson of audio reviews with all this talk of raw power (combined with James May's technical knowledge of course ). If we're doing car analogies, it's more like saying apart from raw power, what value is there in spending money on a brand new VW Golf GTi (external mini-DAC amp) when you already have a standard VW Golf (smartphone) right in your garage (pocket), and you only ever drive it to the shops and back (listen to IEMs) so you wouldn't use the GTi's extra power (volume). Of course, some people like to drive really fast (listen deafeningly loud) on their way to the shops and break the speed limit, risking injury (permanent hearing loss) in the process, but most people don't, and would only ever use their Golf or GTi (smartphone or external mini-DAC) to drive to the shops under the speed limit (listen to IEMs on-the-go at safe volumes). Ok enough of the car analogies.

IEM usage has exploded in recent years (especially with the rise of affordable 'chi-fi' models) and they absolutely do not require mountains of power. You've reviewed a plethora of dongles, USB thumb drive DACs and external mini-DACs like these, which is a great resource for their primary market, IEM listeners. However, it's never been shown that any of these are audibly better than an average modern smartphone that all of us already have in our pockets. You have the chance to show whether this is the case or not, by for example posting full measurements of your Samsung Galaxy S8+, which could save a lot of IEM users money who think they must buy an external DAC as a phone's is not good enough, when this may not be the case. I thought revealing objective truth through measurements, and potentially saving consumers money by showing when it is and is not necessary to spend extra money on audio equipment were among the primary goals of this site. You've measured your desktop and laptop audio and posted full measurements and reviews on them in the past, so I don't really understand why you're not willing to do this for your phone, by posting all the same measurements you made in your excellent LG G7 smartphone review, for your S8+ as well.

 

[Asylum Seeker]

To my mind, this product lags in value. No BT functionality, no internal battery, no volume control. Subject to measurements, the devices to beat in this segment are the Fiio BTR5 ($129) and Shanling UP4 ($99) and UP2 ($79).

The Qudelix is still vaporware, pie in the sky. Let's talk about it only after the consumer can get its hands on it. Until then, the segment leaders are Fiio and the Shanlings.

 

[BurgerCheese]

Samsung Galaxy S8+

The phone that keeps nagging me about hearing loss even though I can hear the neighbors lawn mower louder than the music in my headphones...

 

[wwenze]

At lower digital volumes, would linearity be more important than the SINAD of 0dBFS (or 2V or 2.2V...)?

Multitone looks pretty good too despite SINAD.

 

[amirm]

At lower digital volumes, would linearity be more important than the SINAD of 0dBFS (or 2V or 2.2V...)?

Multitone looks pretty good too despite SINAD.

Distortion component of SINAD is good at nearly -100 dB. it is noise that bumps it up to lower 90s.