The Hifimediy U2 Asynchronous DAC was developed by DIY (do it yourself} enthusiasts in the purpose of making a really good but cheap dac that could compete against regular commercial DAC’s costing many times as much. It utilises a DAC chip from ESS Technology, whose DAC chips is highly regarded. The ES9023 chip is their simplest DAC chip which keeps many of the features of their bigger brothers at a minimal cost.
The Hifimediy U2 Dac works in USB Asynchronous mode using the standard USB Audio protocol. No drivers are needed in Windows, Mac OSX and Linux for up to 96kHz/24Bit Asynchronous transfers.
Asynchronous transfer means that the timing of the data flow is controlled from the device (DAC) instead of from the computer. Computers are not the best to keep a steady clock so it is much preferred to use an external master clock. The Hifimediy U2 is clocked by a 27Mhz oscillator which is buffered by a low jitter PLL1705 as the master clock source.
USB Audio uses Isochronous data transfer in either synchronous, adaptive or asynchronous mode.
- In synchronous mode, the length of a second is defined by the host device. That is, the host will send data at a rate, and the device has to exactly match that rate
- In asynchronous mode it is the other way around, the device sets the definition of a second, and the host has to match the device.
- In adaptive mode the data flow determines the clock.
The U2 uses the SA9023 USB receiver chip from SAVITECH (not to be confused with the DAC chip ES9023). It accepts 32kHz, 44.1kHz, 48kHz, 88.2kHz and 96kHz inputs at 16 and 24bit. The SA9023 USB receiver is set to work in slave mode with the 27Mhz oscillator is the master clock source, buffered by the PLL1705 chip.
The U2 dac can be used together with the USB Isolator. it will isolate the power from the PC and give a cleaner 5VDC power to the DAC. We have experienced improved clarity in soundstage and separation using this isolator together with the Hifimediy U2 and UAE23 dac’s.
Features:
- Asynchronous USB transfer
- Output on 3.5mm headphone jack.
- Volume Level is controlled by the normal volume control keys on your computer. (no need to use the volume control inside iTunes etc.)
- No drivers required for Mac, Windows and Linux!
- Normal line level output (2Vrms) when connected to amplifiers/preamps. For headphones the level decreases down to 1Vrms for 32ohm headphones
- Confirmed working with iPad 3 (iOS 6.0.1) using this USB hub: http://hifimediy.com/index.php?route=product/product&product_id=90
- Quality TYCO gold plated headphone connector
Additional features:
The U2 can also work as Asynchronous USB to optical converter when not using the analog output.
The U2 can also work as Asynchronous USB to optical converter when not using the analog output.
Highlights about Sabre ES9023 dac chip:
- The sound go straight out of the DAC chip and into your headphones or amplifier. It is not needed that the sound signal go through a capacitor to remove a DC voltage, there is no DC voltage to remove! This omits the need of a coloring cap which adds costs and reduces sound quality
- Jitter Eliminator! The ES9023 utilISed patented HyperstreamTM architecture and Time Domain Jitter Eliminator
- 112db DNR
ASIO driver:
Savitech has released an ASIO driver for the SA9023 usb chip. ASIO drivers can provide lower latency, and is to optional to use.
Asio drivers is only recommended for advanced users, and is not required for normal audio playback.
It can be downloaded here.
Asio drivers is only recommended for advanced users, and is not required for normal audio playback.
It can be downloaded here.
Output levels:
- Open 2.2Vrms
- 4.7Kohm 2.1Vrms
- 1.8Kohm 1.9Vrms
- 510ohm 1.5Vrms
- 330ohm 1.3Vrms
- 30ohm 1Vrms
Note: Normally amplifier inputs are from 10K to 100K ohm. Normal headphones are from 32 ohm to 250ohm.
Model:U2-Async
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| Weight | 0.04000000 kg |
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44 reviews for HiFimeDIY U2 Asynchronous USB DAC
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Dave –
I last reviewed this on December 9 2015. It is now July 10 2022. It is still going strong, used every day for 12 hours and on Windows 10, flawless operation. I have other dearer DACs this beats them hands down. Buy it. The only reason I bought other brands was that I could never get them, they were always out of stock.
jompo –
I have successfully connected this U2 DAC on a Galaxy Note 4 with USB-A female to microUSB cable. Fine.
I also use the U2 DAC connected to a C.H.I.P. (the 9$ computer) in order to use the C.H.I.P. as a squeezebox-like device (i.e. network music player), connected to my hifi amplifier (the C.H.I.P. can also be squeezebox server… I used the U2 DAC also on a Raspberry Pi to the same goal).
siketa –
I received my item 10 days after placing an order….very fast delivery from HK to Croatia! 🙂
Comparing this DAC to Realtek ALC269 chip in my Lenovo Z580….the sound at 50% Windows volume is louder, the bass is deeper and punchier at the same time….also more details are present. No need for an amplifier using my Audio Technica ATH-SJ33 (48 ohm). The case is smaller than I thought it would be. Highly recommended as the first DAC solution and entry into the HiFi world. Best buy for sure! 🙂
Dave Bower –
I have had my DAC for nearly 12 months and all I can say is, (It’s Great). Sound is pure, and unlike others here I have had no sound issues with it.On the odd occasion my Windows 7 hasn’t recognised it on startup but remove and re-inserting has fixed the problem.It is in use 12 hours a day, I would recommend it to everyone.
Chiw Soong Wai –
Bought this somewhere in September. The sound is absolutely gorgeous and this really easy too use since the footprint is small. Am a audiophile with many CD player and high end speaker with tube amps for many years. The sound quality coming from this small box is excellent.
However recently now it is bugged with a crackling and distorted sound continuously that I am unable to solve. I have plugged it into different pc and notebook- results is the same. Tried it directly with headphone still the same distorted sound.
Guess this dac may have quality issue. Felt disappointed with the short life. It is running fine till now. Don’t think I will recommend to anyone due to this issue. HIFIME REPLY: it sounds like there is a problem with a capacitor. Please contact us to arrange a replacement, we will send it to you for free, there is a warranty on the DAC.
Salvador –
I’ve just received mine today and tested it in different computers, headphones and amplifiers with several channel-test files and definitively the output stereo channels are inverted. Right sounds left and vice-versa. Is this a defective unit? Hifimediy reply: This seems impossible, please check your cables, headphones and computer settings (try another computer). UPDATE: SALVADOR CONFIRMED THIS WAS A LINUX SETTING ISSUE.
rlube –
I have a Raspberry Pi B Version 2 and am able to get a HiFimeDIY Sabre U2 Asynchronous USB DAC working with it. The only mod is to prioritise USB audio over HDMI and analogue.
I also obtained the HiFimeDIY USB Isolator, but when this is installed inline, the RPi is unable to identify the DAC at boot up. This is not a show stopper, as the DAC is working fine and I am not experiencing any white noise with it. This DAC is only designed to go to 96khz, and I am satisfied with that.
Mathias –
I bought this some time ago when I built my pc. Unfortunately, I regret buying it. I constantly get blops and pops, sounding like its trying to correct itself from falling out of sync. I dont know if my device is defective maybe.. I also bought the Isolator, which unfortunately makes no difference at all. I am really disappointed and will not recommend this product to anyone. Hifime reply: It shouldn’t behave like this, please contact us to arrange a replacement. And the isolator will not help if the problem is with the U2.
Elysée –
Thank you guys for the confirmation and the very good device at reasonable price. It is easy to use and works well with foobar2000 software. I really appreciate it.
Elysée –
Hello,
I’ve received U2 Async DAC yesterday. Really great sound and I like it. I only notice a pop noise from the DAC to the speaker when i’m switching on my computer. Mine doesn’t have green or blue jack connector but something between brown and black color. So I’m wondering if it is an authentic Hifimediy U2. It’s led color is red. Picture in the following link https://dl.dropboxusercontent.com/u/52715730/IMG_20150512_121521.jpg
—-hifime reply:yes it is authentic. We use another connector on last batch, it has LED light built into the connector so provides better optical performance.
golov17 –
Очень музыкальный и стоит своих денег. Рекомендую. Asio звучит хуже асинхронного режима. Драйверы не нужны на WinXP. Спасибо создателям этого маленького по размеру, но не по звуку, DAC! Рекомендую.
Very musical and very good value for money. Recommend. Asio sounds worse asynchronous mode. No drivers are required for WinXP. Thanks to the creators of this small in size but not in sound, DAC! Recommend.
Advid –
Great DAC for great music, really worth the price.
I bought it after stunning blind tests with one I borrowed.
Thank you for this piece of hardware!
(note: on the very first use on MS Windows just wait a moment for the OS to install the drivers, it can take 1-2 mn on some PC, after that no delay on plug-in)
Ovidiu A. –
I bought this small device some time ago, more from curiosity, never listen to any ESS Sabre chip dac before. I wasn’t impressed first time I listened. I used to listen with Centrance DACMini and Audeze LCD2. I used DACMini as headphone amp with U2 as dac. I also tried with Westone W3 and I couldn’t say I liked better as before.
In the meanwhile I acquired some AKG K340 and decided to try it again, since 3D imaging was the forte feature of K340 vs LCD2. This time I was really impressed by the U2 sound vs DACMini’s dac. Even if micro details were less precise, the sound was better localized as soundstage, sound seems to flow naturally, with better depth. Comparing to U2, DACMini’s dac appear to be more 2D than 3D.
Boris –
Very good sound for price, even better after mod. After comparing with referent design shematic for DAC chip I have replaced output foil capacitors with SMD ceramics and great amount of detail was emerged, though on some recordings now it sounds too bright. Compared with Micromega Mydac (after mentioned modification) I can’t hear any difference, which is strange since they use different DAC chips.
Dave –
Today I received my HIFIMEDIY SABRE U2 ASYNCHRONOUS USB DAC & HIFIMEDIY USB ISOLATOR,WOW this truly is a great DAC. I’m pleased I purchased the isolator with the DAC it is a must. It is like buying a new Amp,the sound quality is fantastic with full rich sound and clarity.All my music is in 24/48000Hz Flac and I can really appreciate the music now.It runs into a 100 watt RMS per channel amp driven into 12" woofers & 8" midrange & 6" dipole speakers.Mounted into 1/2" thick MDF enclosures I Made myself , so I am pretty happy with the performance of this DAC. I would recommend both products to anyone.I give it 5 STAR’S. Oh and the delivery to Australia was really fast.
hrubytomas –
Thank you so much for this DAC is a big improvement to the sound of my laptops. It is sufficient as well as my Beyerdynamic DT 990 PRO 250 ohm. Very fast delivery highly recommend it.
Luron –
I bought two items of this tiny DAC, one for me and the other for a friend of mine. It is perfect for listening through my Klipsch ProMedia Ultra 2.0 enclosures or my Q-Jays earphones. The ASIO driver enables to bypass Windows sound mixer. The only con is the weak output level which prevents from using high impedance earphones.
Unfortunately, I have not been able to try it with my high-end HiFi system yet, because I have been away from home for months. It would be interesting to compare this DAC with my HiFi DAC, an old Stello DA220 Mk2, connected to a desktop PC through a M2Tech HiFace USB>SPDIF interface.
Claudio G. –
after some problems with the first DAC2,i received a new one.What can I say? Unbelievable!!! Sound in general is more accurate,more dynamics,a better sound-stage……Perfect!!!! And in conjunction with the isolator and a good signal cable,it’s a must!!!!
But most important is the support and the service that these guys gave me….truly professionals!!!
HIGHLY RECOMMENDED!!! PRODUCTS AND PEOPLE!!!
Ben –
After about 2 weeks, got it today. Very pleased with the sound. Wow…!!!! More clarity and firmer bass. It has more air compared to the original SABRE USB DAC ES9023. Perhaps I should have bought it together with the Isolator, could’ve been a lot better. Ooh welll…., I think it’s going to be my next purchase. Thank you thank you..!!!!! Five stars from me.
Dennis –
I just received this amazing Dac from the mail today and installed it to my hackintosh. I was using a Fiio E10 previously and this U2 sabre really sounds amazing. I’m an audiophile for almost 25 years and have spent most time listening to high end audio. Hackintoshers are always having problems on audio every time there is an update from apple and this is the answer by using this dac and its plug and play on mac. This U2 sabre has a huge and wide sound stage. music has good timbre and uncolored sound. Male and female vocal are excellent. I can hear individual instruments separated from each other including background sound nuisance. Bass are deep and tight and unobtrusive while the treble and high are sweet and airy. My speaker just dissapear in front of me and all I can hear is music singing. This is money well spent.
Ruth –
Excellent! Bought this DAC to use with a Raspberry Pi running piCorePlayer (to work as a Logitech Squeezebox). It already sounds LOADS better than the bog standard audio output on the Pi (even without having given the DAC much running-in) – gone is the annoying hiss when the Pi isn’t playing any music – replaced instead with silence! And the sound is already far clearer when playing music. Can’t wait for a couple of day’s time when the DAC has had a good few hours of running in – I imagine it’ll sound even more amazing then! For the money, it’s a total bargain – it means I can buy a Pi kit and a Sabre U2 DAC for less than the price of a second-hand Squeezebox, and have it play right up to 24-bit 96kHz too – meaning I get performance more akin to a Transporter! Better still, it’s so easy to set up – just plug in to a USB port on the Pi – no soldering required! Totally excellent solution for anyone who loved the Squeezebox and wants to emulate one on a Raspberry Pi!
Mahmood –
Excellent sounding little jewel. Amazing quality for price. As compared to my harman/kardon DAC (Burr-Brown chip), this DAC provides much wider sound stage, much clearer mid-ranges and vocals, and much tighter bass. Noise is well-controlled, even when the dongle is connected to a USB hub. Definitely does not need an isolator if used only with headphones. The only range in which the DAC could potentially perform better is in lower high range, where the sound seems to suffer from some harmonic distortion. But this is noticeable only because performance is so consistent across the rest of the range. I confirm that it works on iPad and on the new Ubuntu 14.04 Trusty. On iPad you may get inconsistent behavior if you connect the dongle directly to camera connection kit. You will need an unpowered USB hub (any hub works) to get around the software limitation imposed by Apple that prevents third party devices to work properly on camera connection kit.
Jens –
superb sounding little DAC.
Very airy, natural, detailed and linaer sound. Does not alternate your music in any way. No background noise recogniseable even on highest volume setting on my headphone amplifier. I am using the DAC with my STAX SR-307/SRM-323 amp electrostatic headphones combo and can very much recommend this combination. With high res 88200 or 96000 Hz FLAC files and binaural recordings for best 3d immersion it’s just fantastic. I downsmple19200 Hz files to 96000 Hz with SoX in foobar2000 and can’t hear a loss compared to my Fiio X3, which is capable of 192000 Hz asynchronous USB playback. I have compared the DAC to my Fiio X3 as external DAC and find the Sabre DAC superior to the Fiio.
Eric –
I’m using this to bypass the crappy on-board sound card on my Asrock motherboard. I’m using Grado SR60s, so definitely nothing fancy. Needless to say, gone is the audible hiss with no noise present, and music sounds wonderful! I haven’t heard music this clear and detailed in such a long period of time.
The only thing negative about this device, on no fault of its own or its designers, is that it doesn’t work with USB OTG for my Moto X or HTC One. I guess those phones don’t provide enough power through the USB port to power the device. I’ve tried a standard USB OTG cable and the special cable that has an additional Y splitter to provide power, but it still doesn’t work. I haven’t seen any mentions of the above combination working, so there you go, it DOESN’T work.
I’ll probably try a powered usb hub soon.
Fabio –
Superb. Detailed, airy, balanced, rhytmic. For the price, a bargain.
Rudy –
Just received this a couple days ago. I have it hooked up to a Macbook, feeding into an old Hitachi tube amp and a pair of 3 way Infinity tower speakers. I use it mostly for streaming audio or ITunes playback, plus occasional FLAC playback through VLC. It works great! Sometimes when I first hook it up or switch between applications there’s no signal for a very short while – closing and reopening the offending application has always fixed this so far. Otherwise it’s awesome. Sounds good, and louder for whatever reason than the built in Macbook audio port which is an unexpected bonus. I was worried it might just reveal all the flaws in my terrible low quality sources, but nothing sounds worse and it’s actually fixed a mysterious mid-range grinding sound that was happening intermittently. High quality FLAC files sound awesome, of course. Highly recommended – at this price you don’t have much to lose.
DJAGAB –
I am usually very sceptical when it comes to other’s opinion about sound quality. So I decided it was time to give it a try myself and I bought this little piece of art. I did an A-B comparison with a sound card that is supposed to be high end: Audiotrak Prodigy HD2 Dl. I had a very hard time distinguishing between A and B. That’s a good sign! The DAC’s sound is very detailed over the complete range of supported sample rates. I did not believe that a piece of electronic could sound even sound better after a short run-in time. This Sabre DAC proved otherwise. The sound can only be described as more relaxed, when adding the DC-DC converter in between. In our country we have a saying for buying something that’s not worth the money: "To buy a cat in a bag." The Sabre Async DAC is definitely not a Cat bought in a bag, but more like a Jaguar for the price of rusty Renault. Keep up the good work guys!
dregnier –
Vu le nombre d’avis qui encense ce produit, je vais être à contre-courant.
Personnellement, je n’entends aucune différence entre le rendu sonore avec ce DAC Sabre U2 et mon ancienne configuration. Déçu !!
Dave –
Bought one of these along with an isolator to plug into a Raspberry Pi running Volumio. Sounds fantastic and supports hardware volume control.
Michael –
Exceptionally good. The sound is equivalent to an asynch DAC I spent 6x as much money on.
Corley –
This thing is fantastic. It was rather needy of a burn in process though. It sounded harsh and too tight with sibilance straight out, after about 12 hours of burn in – it was showing signs of clarity with the treble becoming strong but still a little harsh. It’s been a few days and now it has no sibilance, no harshness and is opening up wonderfully. The balance across bass, mids and treble is now straight and pure. It’s the best thing I’ve ever heard with my Beyerdynamic T1. I’m hearing new things in everything I have. wow.
Fabio –
Has anybody used Sabre U2 Asynchronous USB DAC with openelec or raspbmc linux distribution? I tryed with both of them on my rasberry pi but it doesn’t work.
Fabio
(admin EDIT: merged 2 reviews):
I found that OpenElec doesn’t support extern usb audio device. But with Raspbmc Sabre U2 Asynchronous USB DAC souds great!
Chas –
After I accidently stumbled across this site when searching for a Sabre DAC I saw the U2 Asynchronous DAC and thought that I would buy one and try it out just out of curiosity and I am glad that I did! This is a simply amazing DAC for the price.
I have been into Hi-Fi for many years and have heard many different CD players and DAC’s and I can honestly say with confidence that this is one of my favourites. The sound quality that comes from this device is very nice, detailed, smooth and warm and it seems to sound right in all area’s (Bass, treble and mid-range) but I would recommend using it with the USB power isolator which you can also buy here. I’m not just saying that to make you buy it but it makes a huge improvement to the sound quality. I also used the AISO driver to get bit-perfect sound from lossless files and it sounds so good! If you don’t believe me buy one and find out! This DAC is a giant killer for certain.
Johan –
Totally Worth It! (Had tried some dacs, but this totally surprised me in a very good way)
Speakers Equalized with Equalizer APO (system level eq!) for windows (Open Source, sourceforge)
(REW and Equalizer APO works well)
Used Umik-1 Mic for equalize the speakers for clarity (Superb sound)
Really Love This DAC
Fabio –
FedeVi quanto hai di tasse?
reply: Around 20% we believe. You can use Beligum post to avoid having to pay import tax.
This is not a review and will be deleted soon.
Fabio –
How much is it of tax for an italian buyer?
reply: Around 20% we believe. You can use Beligum post to avoid having to pay import tax.
This is not a review and will be deleted soon.
FedeVi –
Davvero un buon prodotto e ottimo miglioramento rispetto alla scheda integrata del pc, non avrei potuto aspettarmi di meglio. Arrivato nei tempi indicati e perfettamente funzionante, basta settarlo come dispositivo predefinito di riproduzione audio dal controllo volume di windows.
An impressive product and a big improvement over the pc onboard audio card. You plug it in, wait for the automatic driver installation, set as default audio device and you are good to go.
(OS: win7 64 bit)
Chris –
I am enjoying the lovely sound of this little thing! Very detailed to my ears. Try it out! 🙂
Jorge –
This U2 async is an absolute BEAST. I have to admit that I was not expecting very much considering the price but I was totally wrong! Very clean and musical with a touch of sweet, detailed sound without signs of excessive brightness.
In fact I like it more than my Cambridge audio combo that it costs me around 900€ three years ago. Impressive.
I wonder what would happen if hifimediy makes an upgraded UAE23+ with async usb with several spdif inputs and balanced XLR outputs…
richard51 –
I am very pleased with the asynchronus version of this dac……. Great differences vs. the synchronus version……For the difference in dollars a bargain…..I am sure that there is better dac out there BUT i am sure that you would pay a good amount of money to have a truly better sound and not just a marginally amelioration… Buy it…. and invest in the headphones or in the amp… This is my conclusion
m randle –
I love this thing, could hear the improvement over my pc onboard sound straight away. Very simple to set up, just pluged it in and pointed vlc and deadbeef to it (ubuntu 13.10).
I have a very modest setup and i don’t believe i will feel the need to change any of it in the near future…….
Linux based htpc > HiFimeDIY Sabre U2 > t-amp (smsl sa-s3) > Cambridge Audio S30 speakers.
reno –
Mêmes qualités que pour la version synchrone (http://hifimediy.com/index.php?route=product/product&product_id=83) mais, grâce au S9023 (qui remplace ici le Tenor E7022), en asynchrone.
Donc, concernant l écoute, l ES9023 (http://www.esstech.com/PDF/ES9023%20PB%20Rev%200.2aPB%20110117.pdf) est vraiment exemplaire.
On retrouve la même signature sonore. Les dynamiques sont respectées sur lensemble du spectre audible et lanalyse est poussée à lextrême.
Fonctionnel avec les OS libres comme Debian, OpenELEC, …
Un excellent "petit" DAC à toujours avoir avec soi.
Guenther –
Fast Shipping, works well with Ubuntu 13.04 (with Alsa & MPD) in Bitperfect Setup.
Connected to a Tripath, it sounded VERY good! (i have a lot of different DACś)
Fast Shipping (5 Working Day from Belgium to Austria), unbeatable Price.
Arie –
I had the normal ‘non-asynchronous’ version of this and liked it a lot. Ample others too, given all favorable reviews. This one is even better. I was not really expecting much of a difference, but I was wrong. In my setup the sound is more detailed, yet more relaxed. Incredible bargain!