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stoner acoustics ud130

Discussion in 'Portable Headphone Amps' started by scruffy1, Oct 28, 2019.
  1. scruffy1
    if you just want the review, scroll past the italics to the bold font, and it starts below that.. but if you want to hear how i came to buy this product, read on....

    the back story is that i am a relatively late arrival at the dac / amp scene, although i have absolutely loved my audiotechnica ad700's for over a decade, starting with a chaintech av-710 software modded to use the wolfson dac it contained, and then ultimately on to the asus hdav line that allowed me to play with op amp rolling

    however, most of my "serious" listening was done using an htpc, with an asus hdav1.3 sporting a burson v5i opamp upgrade, and thence via a nad d3020 to a set of wharfedale 10.1's with a 10.gx subwoofer

    up in the bedroom though, it's neutron accessing the home server via wifi, and then i bought a cmoy amp (the altoids tin one) which revealed there was more quality to be had using a discrete amp

    my curiosity had been piqued, and the next step was a rather major jump

    on a whim i bought a pre-loved alo pan am, and it was an entirely new experience hearing my flac collection, some of the songs that'd i'd known and loved for close to half a century revealing details that had never been heard before

    shortly after that i managed to also procure some pre-loved akg Q701's, and between rolling the valves to nos russian stock that had been included along with some french ones, i lucked out on synergy and pretty much hit peak listening thus far in my experience

    it's only fair to suggest that anything else would be pushing it to improve on that unless i bleed significant finance into the task

    that is, until i grabbed a khadas tone board too, and had to reconsider what half a decade of dac progress might be able to bring to the table...

    i know this is a rambling intro, but it all comes around to explain my journey, and to put my introduction to stoner acoustics into perspective

    in the protracted period i was awaiting the proverbial slow boat from china to receive the khadas, further opportunity to experiment arose on the nerd forum i shop at for a lot of computer gear, and i was introduced to the stoner acoustics ud110v2 - something i had until that point not even known was a thing

    there's plenty of positive commentary on it in this very forum here :

    that was me done for, and it got to me in the brief gap before the khadas finally landed

    in essence, it completely blew away the asus xonar d2 in my desktop as a source; my klipsch 2.1's, which i had thought were pretty mediocre were suddenly revealed as surprisingly musical, and sweet and crisp and clear

    even the hdav with the burson op amp was outclassed, by a dinky usb stick of a thing !

    dang ! then the khadas arrived, and it was astounding to me

    the age of discrete internal sound cards, even with excellent op amps helping them up, was over, and relatively cheap external dac / amps had made them redundant

    i was eyeing the stoner ud125 on special, due to being superseded, and then couldn't resist the ud130, which rocks the latest akm dac chip

    i figured the khadas gave me a taste of the current ess chip; the pan am uses an older wolfson (a sentimental favourite after chaintech started me on the journey), and the ud110v2 is a texas instruments dac, so i'd have had a pretty decent smorgasbord of available families

    so, after that lengthy prologue, onto the review (finally)

    the ud130 arrived safely in a padded envelope containing a pink zippy case, not unlike a digital camera case, which also contained a short but functional micro usb 2.0 cable

    i paid $80usd plus $6 postage, that's $127.50aud all up at the prevailing exchange rate at the time; it took 17 days to get to me

    per their own info online :

    Savitech SA9227 USB Audio Receiver
    AKM AK4493 High Performance DAC
    TI TPA6120A Dual Channel High power Amplifier
    USB Audio Class 1.0 24Bit/96KHz
    USB Audio Class 2.0 32Bit/384KHz, DSD-64/128/256, DoP-64/128
    0.5dB/Step Digital Attenuation (255 steps)
    Select-able LOW/HIGH Gain
    THD(%): <0.001% 20Hz-20KHz

    Package Includes:
    1x Stoner Acoustics UD130
    1x USB 2.0 Micro USB Cable
    1x Carrying Pouch
    1x 1 Year Limited Warranty

    Weight and Dimensions:
    58mm (Width) x82 mm (Length) x 17mm (Height)
    110 grams

    the whole thing is encased in a nicely solid black anodised metal box, with (i guess) brass bolts securing the front and back plates; it looks utilitarian and might be tarted up with some nice matching black hex nuts in place of the contrasting ones - that's my computer building pedigree urging me to pimp any case

    basic, functional, not unattractive

    front oblique.jpg

    on the front is a standard 3.5mm stereo jack, next to which is a multi-colour led to show the setting, then a button that cycles low / high gain, and with a long press makes the jack into a line out signal, bypassing the amp and giving you stand alone dac capability

    the volume knob is analogue in feel, but actually works digitally to give very precise (and balanced) control


    the back has a micro usb b connector, and a small 2 position switch to select usb 1 or 2

    my thoughts on the ergonomics ?

    it works pretty well, although the supplied usb cable is too short to be practical - no great drama using it with a pc or laptop, but for (android) phone as your source, you need a longer otg capable connector

    the supplied connector is a rather tight fit in the usb, requiring some grunt to both connect and disconnect - which is a mixed blessing although probably advantageous to keep it where it needs to be if you are using the ud130 as a truly portable unit rather than a stationary item

    i managed to daisy chain a short one i already had, and it worked fine with my elderly nexus 5, but i'm waiting out on the arrival of a longer single otg cord for more practical use as my bedside system from here :
    3 weeks and counting so far :wink:

    the usb selector switch is simple and functional, and an agreeable length to be easy enough to use without sticking out enough to accidentally knock to the other position

    the headphone jack is good, as is the button

    the led light is annoyingly bright; blue led was pretty schmick last decade, but given the device powers on via usb, it is obviously "on" if you plug it in, although i guess it's a very visible reminder it's draining your phone battery if you forget to unplug after use
    high gain is a more purple hue (not by much at full luminosity), and the line out is a less intense (but bright) red

    i initially attempted to temper it down by jamming some paper inside the case, over the led (visible in the front photo), but it was still very bright, and the resultant seal over the small front hole made the unit heat up more than allowing the air flow that the led "port" and the usb "gap" seemed to create

    plan b was to attack with the multipurpose sharpie, and black out most of the front of the led, smothering the transmitted light quite effectively, and for my purposes, agreeably

    a way less powerful led would be welcomed by me, but maybe other people enjoy a well lit bedroom...

    the volume knob feels nice to use, and the gradient is practical for adjustment - full rotation is from about 7 o'clock to 5 o'clock; initially it looked a bit long, and i'm not sure how practical it might be in a pocket, but that won't be an issue for me in the situation i am employing it

    inside the build is tidy

    board top.jpg

    the quality of soldering looks good, and the components are revealed for the nerds to identify

    the naked pin headers near the volume knob make me wonder if there's opportunity for upgrading the firmware or other shenanigans, but there are no instructions suggesting that possibility

    board base.jpg

    the underside of the board is pretty sparse, but shown for completeness

    so, most importantly, how does it sound ?

    lovely !

    my observations (both plus and minus) - noting that it is unfair to expect a keenly priced dac /amp to compete with a stand alone more expensive dac, and a way more expensive dac / tube amp, but that's what i am already used to hearing

    the source is a nexus 5 phone, running lineage 15.1 (android 8.1.0); i am mostly using flac files through neutron music player

    • the reproduction is very clear and with a wide sound stage; the separation is more than the khadas, but the depth is not as natural - it's like the music is lined up across your hearing rather than the 3d the tone board conjures
    • impressive silence (no background hiss discernible between tracks, or in quiet passages)
    • the low volume is impressively balanced (unlike the cmoy that needed a nudge before both ears got a similar volume; this is good from the get go on that score)
    • it's markedly better than the ud110v2 - clarity, tone, stage, but noting that the 110v2 blitzes any internal sound card i have used prior, all of which were good; in essence the improvement of an already exceptional dac for the price shows that stoner acoustics are evolving their products impressively each new iteration
    • the reproduction is a little harsh with the akg q701's, but in this case i am spoilt by the warmth of the valve amp i am used to, and as stated earlier, the synergy of that combo is the peak of my experiences thus far, and in any case way more expensive kit
    • listening with the ad700's in bed (the purpose of the buy) is a success - way better than the cmoy (even with the v5i installed in it, which is rather nice), and noticeably better than the ud110v2, which itself is no slouch
    i suspect the ud130 might pair even more comfortably with a less analytical set of cans - there is a myriad of well defined and articulate detail in the reproduction, but with the width comes a sort of sparse "gap" between instruments that sounds slightly unnatural - not unpleasant by any means, but maybe more clinical than some listeners will enjoy and perhaps a bit more fatiguing than the valve sound i am far more used to, of late

    at the price point, i have no cause for complaint - the ud130 is in every sense superior to any of my other "lower end" gear, and punches above its class compared to significantly more expensive components

    a closing observation is that if you are using it as a stand alone powered by the phone, you will not be in it for the long haul without sourcing some add in power option - i reckon 4 hours maximum on the nexus 5 's battery (streaming flac via local wifi) would be all you could milk

    all in all the stoner acoustic ud130 is a substantial step up in quality from onboard (and sound card) dac sources, and offers considerable listening return for your investment
    Last edited: Oct 28, 2019
    Chris Kaoss and fonkepala like this.
  2. baskingshark
    Nice impressions, I also own the Khadas tone board and am very impressed with it.

    How does this Stoner acoustics fare with super sensitive IEMs? Any hiss?

    And does it in any way colour any frequencies in the music?
  3. scruffy1
    i've got a pair of tin audio t3 and it works well with them; not sure how sensitive they are considered

    no, there is no discernible hiss... despite my ears being ancient, they are well protected over the years, and i am both extremely sensitive to quite faint sounds, although i expect my upper register perception is diminished by age - indeed, a quick headphone test on pure tone shows i am lost somewhere above 14khz, as i hear it but not 15khz :frowning2:

    so if there's hiss, it's above 14k

    i do hear hiss using the altoids amp at low volume, so i surmise the stoner doesn't produce it for the t3's

    i'm personally disinclined to use iem's - they are not that comfortable for me (and i have tried foam and silicon plugs), and the sound quality is not up to the ad700's
    i found the t3's useful due to their size and passive noise cancelling being beneficial in a plane, but i'm not sure they are my thing

    i'm not that guy to cocoon myself out in the day to day world; my listening is in bed, or at the desk (with cans), or transfixed in front of the stereo on the comfy lounge, listening to quality reproduction instead of being lost in netflix or even worse, free to air (pah !) which appears to be more ubiquitous, beyond my comprehension

    does the stoner colour it ? i think not; given both my headphones are open back and noted for neutrality, i can't hear it, whereas the pan am i think adds a certain warmth that tubes are alleged to impart
    so i am saying it's pretty much a "flat" and sincere reproduction for them

    the tin audios have a much less flat response, and i don't use them enough to be accurate, but the sound spectrum is biased to miss lower mid and upper bass (though they do bass surprisingly well), and the upper end is more harsh, though not sibilant, maybe because that is above my threshold to notice

    i'm still pretty new to analytical listening - i know what i like, but i am just beginning to understand the nomenclature surrounding that experience enough to describe it in the correct terms that more seasoned audiophiles would nod approvingly to hear

    hope that helps
    fonkepala and baskingshark like this.

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