1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.

    Dismiss Notice

Stoner Acoustics UD125 AKM AK4490 USB-DAC & UDX & UDXA Thread (Impressions, Discussions etc.)

Discussion in 'Portable Source Gear' started by HiFiChris, Jun 10, 2017.
  1. HiFiChris Contributor
    Have you ever heard of Stoner Acoustics? You haven't? Well, I haven't either before 2012 when they were mentioned in a German audio community I was active in at that time. 2012 is also the year they were founded.

    If you are wondering about the slightly inappropriately seeming name - according to the company's information, the founder of the Malaysian company wasn't aware of the slang meaning of "Stoner" when he registered his company that was originally meant to be named "Stone Acoustics", representing the steady and calm nature of a stone or rock, however as "Stoner Acoustics" sounded phonetically nicer, this is the name he finally went for.
    While there were thoughts about eventually renaming the company, they had already built up some reputation, so for now the name will remain - and you gotta admit that it is quite catchy, isn't it?

    Photo ©opyright: "HiFiChris".

    Having started with a small blog and offering a simple and case-less USB DAC chip in the beginning, they eventually evolved into a proper company with a full website and more complex products, one of them being the UD125, a USB DAC that is using AKM's AK4490 DAC chip, along with a Texas Instruments TPA6120 amplification chip. According to its product site, its output power is rated at 350 mW per channel with a line output capable of outputting 4.88 V (RMS) and four selectable digital filters. The DAC is priced at USD85.

    I have a copy of the UD125 with me and can report that it is a very nice USB DAC if you are looking for an affordable option that has got a very low output impedance (I measured and calculated it to be just tiny 0.1 Ohms), along with a really precise volume control (256 steps with a linear step size of 0.5 dB each).

    It definitely is an interesting device, and impressions as well as discussions are highly appreciated and welcome in this thread.
    Last edited: Jun 10, 2017
    cardeli22, mgunin, stalepie and 2 others like this.
  2. HiFiChris Contributor
    Well people, here is my review of the UD125. As you will notice, it's written in German language. Don't worry though, you don't necessarily have to use the often quite difficult to understand Google-based translation, but you can use https://www.deepl.com/translator instead - it's a machine-learning-based translator as well, however it is usually more accurate than most other freely accessible alternatives (you might however have to translate the review paragraph by paragraph as it seems like it is too long for the full text to be translated).

    Anyway, here you go:

    Last edited: Feb 10, 2018
  3. tarhana
    really nice find Chris. how is the battery life?
  4. HiFiChris Contributor

    It doesn't have a battery since it is USB-powered. :wink:
  5. RAQemUP
    So when used as a amp/DAC, Does it receive power from the device? If so how much is the power draw?
  6. HiFiChris Contributor
    Yes, that's how it works. I will try to measure the voltage and current draw maybe tomorrow or on Monday (if I don't forget it).
    I'll also test whether it works with portable devices (for example Android, iOS and iPod Nano 6G/7G OS).
  7. HiFiChris Contributor
    So the past hour I did some testing with different devices and these are my notes:

    So it was recognised by my Nexus tablet and the Diamond X smartphone, however no sound was coming out; for portable apple devices (don't know about the iPad), there is too much current draw for it to be working.
    Not much of an issue in my opinion though, since the DAC was designed to be used with a PC/Mac.
  8. teston
    I'm glad that UD125 finally has a dedicated thread. I have this for 7 or 8 months until now. Very nice sounding dac/amp with neutral and slightly warm signature.
    If you want to use it with mobile phones then a splitter micro usb will help. By this way the UD125 will draw power from external source instead of the mobile phone. However you will want to bring a power bank.
    For me, I use it as desktop solution and have another dap on the go.
    Last edited: Jun 11, 2017
  9. HiFiChris Contributor
    Nice to encounter other people who have experience with the UD125.

    What phones did you get the UD125 to work with?
    It's a little strange that my Nexus 7 (2nd generation) and Diamond X can transfer enough power to the UD125 to make it "operable" but don't seem to output any digital audio stream to it (which is strange since the Diamond X works perfectly with my Chord Mojo and I could also use the HiFime 9018d with my Nexus 7 (using the Tidal App with my 6 months subscription that was a part of the Echobox Explorer campaign that I backed on Indiegogo)). Is perhaps special software such as the USB Audio Player Pro required?

    Could you share a link to where you found that adapter (preferably from a store that ships internationally)?
    I do have a multi-purpose adapter with an external power input, however it didn't seem to work with my iPhone 4 when trying to plug the LH Labs Geek Out IEM 100 into it (not a single LED would light up and my iPhone said "unsupported device" or something similar).
  10. teston
    I bought it off an AliExpress store
    Leory High Quality Micro USB Male To USB Female Host OTG Cable
    You may want to look for other store since the shipping time is quite long (nearly 2 months for me)
    I use it with my Xiaomi Mi4 and Xperia ZR, working flawlessly.
    I think software won't help because the US125 draws too much power (0.5A). There maybe some phones that can output that much power from usb output but I haven't see one. If it do then the battery is drained fast so I won't recommend it.
  11. HiFiChris Contributor
    For those who are interested, my review is up: [the review is in the 2nd post]

    DSC03742-small.JPG DSC03769-small.JPG

    It's written in German but there's a Google Translate option.
    Last edited: Feb 10, 2018
    golov17 and palermo like this.
  12. thamasha69
    I recently received my UD125 and finally have been able to listen a bit today. Thus far, I am really pleased with the sound signature- exactly what I was seeking. My 1st gen Shuffle has a nice low end, warm sound, and great separation that I was hoping I could find in USB DAC/Amp device for use with my computer and possibly iPhone. The HifiMeDIY 9018 I got last year has been nice and is quite a detailed sound, yet at times I would get fatigued with the treble on certain tracks. The UD125 so far seems to be giving me exactly what I was seeking. It has a warmer, more analogue sound- details, however, are not lost and treble is present but not ever harsh or too present. It sounds really, really good and I look forward to listening over the long term to see how these initial impressions hold up.

    IMG_1472.JPG IMG_1474.JPG
    mgunin and HiFiChris like this.
  13. lynx121
    Hello. Any problems on using this on USB 3.0 ports? Also, anyone compared this to Modi 2/Uber, ODAC, or the new jds labs OL DAC?
    Last edited: Jul 24, 2017
  14. HiFiChris Contributor
    Haven't had any so far on my laptop's USB 3.0 output.
  15. Negakinu
    I've used my tiny UD100 on my Android phone for years. Massive upgrade from the stock headphone out. I used it in combination with a Headstage Arrow amp. It doesn't get recognised by all phones/Android ROMs, but installing USB Audio Player PRO fixes that. I'm going to check out this UD125 as well.

    Here's how the old UD100 looked. :)

    cattlethief and thamasha69 like this.

Share This Page