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Geek Out IEM 100 USB DAC and Headphone Amplifier

  • Geek Out IEM 100 is an on-the-go, high-res DAC (digital-to-analog converter) and headphone amp that plugs into your computer's USB port and is tunes specifically for in-ear monitors. It decodes and amplifies your digital audio so your rad headphones can really sing. High performance isn't just for audiophiles anymore. Know what it's not? Mumbo jumbo. Nor is it hocus pocus. Geek speaks audiophilese so you don't have to. It's simply the best sounding awesomifier you'll ever own. "Man, that thing was so airy, tight, and downright exciting to listen to. I don't think I've heard a USB dongle-type head-amp/DAC with the overall authority and SLAM of the Light Harmonic GEEK yet. That's why all I can say is WoW!!" Michael Mercer Reviewer, Audio360.org "The best gear for listening to high resolution audio." Michael Hsu The Wall Street Journal "What is Geek? In this case it's an ingenious USB DAC (digital to audio converter) that uses the power from your computer to drive even the beefiest headphones and give you true Hi-Fi sound. It truly defies description just how good audio sounded through this system. Simply put, it made me cry with joy. I'm not kidding." Zuke Arakaki Stolendroids

Recent Reviews

  1. HiFiChris
    This little Geek is purely awesome
    Written by HiFiChris
    Published Aug 11, 2015
    Pros - stunning sound quality, perfect for IEMs, almost no hiss with super-sensitive IEMs, sampling rate display, 64 Bit volume control, two digital filters
    Cons - some hiss with ultra-sensitive IEMs, somewhat rickety buttons, heat (due to Class A amplification)
    LH Labs Geek Out IEM 100 Review

    Before I start with my actual review, I’d like to thank the guys at LH Labs for sending me a review sample of the Geek Out IEM 100 (hereinafter also called “GO”).

    Most desktop computers and laptops only have got a low quality standard audio card inside which is not really satisfactory for higher-end audio enjoyment in most of the cases. They often suffer from a non-linear frequency response all over the audible spectrum, high ground noise which sometimes is even audible with big cans, audible distortion and/or bad sonic quality in general. It often gets worse if you connect your high-end in-ear monitors with multiple Balanced Armature transducers which demand even higher standards of the sound card because they require a low output impedance of the source to not suffer from an altered frequency response. Furthermore, they reveal hiss much easier than any full-size headphone due to their ultra-high efficiency.
    Admittedly, there are some good internal sound cards, but they can’t be installed in a laptop, aren’t portable and aren’t really compatible with high-end in-ears in most cases. In addition, they pick up noise interference from the components inside of the PC so easy; and this picked up interference noise will be transmitted through the audio path and is often audible.
    That’s where portable external USB DACs with integrated headphone amplifier get into the game: they’re usually small, portable, don’t need a separate power connection and are far less prone to interference from the internal computer components – the Geek Out IEM 100 which will be tested extensively in this review also belongs to this category.

    About Light Harmonic/LH Labs:

    With the introduction of the Da Vinci DAC, the world’s first DAC that was capable of handling files with a bit-depth of up to 32 bit and a sampling rate of up to 384 kHz, Light Harmonic got known as a trend-setting company in the audiophile world.
    Further versions and evolutions of the Da Vinci DAC followed.

    With the devices of the “Geek” series (that are, by the way produced in California, too), LH Labs, a division of Light Harmonic, has developed high-end audio devices with premium components for a comparatively low price. The campaign was financed by crowdfunding and brought forth the ultra-portable Geek Out USB DAC-Amps as first product of the line-up, followed by the Geek Pulse, a desktop DAC with built-in headphone amplifier; with the Geek Wave, a portable Hi-Res DAP is going to follow in the near future.

    Technical Specifications:

    current MSRP: $189
    frequency response: 20 Hz – 55 kHz (-0,1 dB)
    maximum power output: 100 mW @ 16 Ohm
    maximum output voltage: 3.4 V (RMS)
    THD+N: 0.01%
    SNR: >101 dB
    input: USB 2.0 (asynchronous)
    outputs: 2x 3.5 mm analogue stereo jacks
    output impedance: 0.47 Ohm (right jack), 47 Ohm (left jack)
    amplifier: Texas Instruments TPA6120A1
    amplifier type: Class A
    DAC: ESS SABRE 9018K2M
    USB Controller: XMOS XS1-SU01A-FB96
    supported sample rates (PCM): 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz
    supported sample rates (DSD): 2.8224 MHz, 3.072 MHz, 5.6448 MHz, 6.144 MHz
    supported bit depths: 1 bit, 16 bit, 24 bit, 32 bit
    volume control: 64 bit
    buffer: three-layer buffer
    digital filters: 2 (TCM, FRM)
    chassis: CNC machined T6061 aluminium
    dimensions (w x l x h): 35 x 75 x 13 mm
    weight: 36 g

    Delivery Content:

    The Geek Out IEM 100 comes in a cardboard box with some text on the back that is written in a very humorous way. Inside, you’ll find a quick start guide (that is, by the way, also written in a humorous manner), a carrying pouch and a short USB extension cable.

    The Box and the Geek
    IMG_20150802_120720.jpg   IMG_20150802_120735.jpg   IMG_20150802_120747.jpg
    IMG_20150802_120804.jpg   IMG_20150802_120844.jpg   IMG_20150802_120918.jpg
    IMG_20150802_120953.jpg   IMG_20150802_121046.jpg   IMG_20150802_121010.jpg

    Looks, Feels, Build Quality:

    I really like the plain black looks of the GO.
    Its black CNC machined aluminium chassis is made of two pieces and has got the “Geek” logo on top which is encased by two converging lines that form some kind of acute triangle that also holds the LEDs for determining the sampling rate. On the bottom side, there’s a mirroring sticker telling you which LED stands for which sampling rate, and it informs you about the output impedance of the two output jacks as well.
    The two silver aluminium buttons (one is concave, the other convex) for switching between the two digital filters are located on the GO’s right, the USB plug is on the back.

    The aluminium enclosure lacks any sharp or scruffy edges and feels as well sturdy as valuable; the LEDs shine evenly. One thing that’s less premium is the feel of the two buttons which are quite rickety, but that’s my only criticism in this regard.

    Driver Installation with Windows:

    With Windows as operating system, plug & play does not work with the GO, but it’s not that tragic at all as downloading the drivers from the LH website is pretty easy and installation goes very fast, easy and pretty much automatically as well.

    Here are some impressions of the download and installation process:

    Download the latest driver package from the LH website:
    Open the file:
    Wait for the installation to be completed:
    Select the LH Labs Geek Out in the Hardware and Sound
    settings in the Control Panel:
    Use the volume control in the LH Control Panel for
    finer-grained adjustment steps:

    The playback software should support ASIO drivers for bit-perfect audio output, wherefore I use Foobar 2000 with ASIO and SACD plugins and select the Light Harmonic ASIO Driver in the Playback → Output → Device settings.

    Along with the audio drivers, the Light Harmonic Control Panel is installed which allows you (among other things) to adjust the GO’s volume, what I highly recommend, as the standard Windows mixer doesn’t allow you to make fine-gained adjustment steps with the Geek Out – one percent in the Windows sound mixer results in a huge rise of the GO’s volume.
    After disconnecting the GO from the computer, the last volume setting is stored in the Light Harmonic Control Panel, which is quite handy in my opinion.


    A really convenient thing about the GO is the presence of two audio output jacks, whereby both have got a different output impedance that is stated on the sticker on the bottom side.
    The right one with only 0.47 Ohm is ideal for every kind of headphone, but especially for critical IEMs with multiple BA transducers that require a low source impedance due to their impedance characteristic to not suffer from deviation from their original frequency response.
    With an output impedance of 47 Ohm, the left jack is predestined as Line Out jack, but also good for big circumaural headphones, since some people prefer them with a higher-impedance source.
    Headphones with lesser efficiency may be not loud enough for some people due to the Class A amplifier’s (yeah, the guys at LH really put an analogue output stage amplifier into that little chassis) output power was limited to 100 mW which was chosen to gain a more fine-grained volume control for highly sensitive IEMs that don’t require much power. And yeah, this decision is in my view a very clever one as the volume control (in the Light Harmonic Control Panel) is very accurate and allows tiny adjustment steps that help you to find the exact volume level you are looking for.
    Another cool thing about the GO’s digital volume control is that it operates with a resolution of 64 bit, which means that there will be no reduction of the dynamic range, even at low listening levels, regardless file format, bit depth and sampling rate, what separates the GO from other DACs/Amps with digitally operating volume attenuation that usually use 24 or 32 Bit for volume adjustment.

    On the Geek Out’s upper side there are some LEDs that allow you to calculate the current sampling rate with a little mental arithmetic.
    By the way, the Geek Out adapts the Da Vinci DAC’s ability of handling files with a resolution of up to 32 bit with a sampling rate of up to 384 kHz.

    Sampling rate display:
    IMG_20150803_191228.jpg   IMG_20150803_191229.jpg   IMG_20150803_191502.jpg

    Another neat goodie the GO offers are two user-selectable digital filters by pressing the silver aluminium buttons on the right-hand side.
    When you connect the DAC to your PC, the standard filter is set to TCM (Time Coherence Mode), a minimum phase digital filter with time optimisation algorithm that removes pre-ring and the thereby occurring echoes, what is supposed to optimise soundstage reproduction and therefore enhances sound quality and naturalness.
    Pushing the concave button switches digital filters to FRM (Frequency Response Mode), a slow roll-off filter with frequency domain optimisation that lowers distortion in the upper frequencies.
    When selecting TCM filter mode, three LEDs light up temporarily and two LEDs when choosing FRM filter mode.

    A novelty in the audio-scene the GO has got is a patent-pending three-layer buffer that is similar to the buffering mechanism some computers use, which removes undesired jitter.


    For testing GO’s sonic qualities, I used three of my IEMs (Shure SE846, Ultimate Ears Triple.Fi 10, Ultimate Ears Reference Monitors), as well as two of my circumaural headphones (Audeze LCD-X and the cheap Superlux HD681).

    Music files were ordinary CD rips (16 bit, 44.1 kHz), Hi-Res material (24 bit, 192 kHz), DSD files and MP3s (320 kbps cbr).

    Output Impedance, Frequency Response:

    The GO’s impedance is stated to be extremely low at 0.47 Ohm on the right jack, a perfect electric value for critical IEMs.
    But is this very low impedance also achieved in reality? Yes, it is, as my measurements below prove: even with the Triple.Fi 10, an impedance mimosa that shows much deviation from ground line the
    higher the output impedance gets, the frequency response that is output on the 0.47 Ohm jack stays commendably flat:

    StandardFilter.jpg   SlowRoll-Off.jpg

    Frequency response is perfectly flat all over the audible spectrum even though an IEM with critical impedance response is connected as load, and even though the IEM’s impedance in the bass is very low, there is not a single sign of bass roll-off – the guys at LH Labs really know what they are doing.

    What I personally find nice, too, is that the slow roll-off filter is implemented rather gently to the frequency response, wherefore its focus lays more on the other parameters like total harmonic and intermodulation distortion.



    The main criteria for perceiving hiss is the headphones’ sensitivity (for example: a device has to be a total misconstruction if you are able to hear ground noise with a low sensitivity circumaural can), but one’s personal perception and sensitivity to hiss also plays a huge role – I for my part can say that I am a pretty hiss-sensitive person.

    For testing ground noise/hissing, the first IEM I used was my Shure SE846 which is among the most hiss-revealing IEMs in my collection due to its high sensitivity and low impedance.
    First listening tests were made at rather low volume levels: yes, there was perceptible hiss when playback was paused and even some during playback. Turning the volume up to average listening levels, hiss was still a bit present, but very hard to detect. As I turned the volume up a bit, it was completely covered and gone.
    I’d say that the Geek Out IEM 100’s hissing is about between the level of the first generation FiiO X3 and iPhone 4, therefore still clearly on the low side.
    The GO’s ground noise is by far less than with the FiiO E6, Electric Sumo DIY cMoy and iBasso DX50 (which had too much hiss for me that I had to sell it just three hours after I received it).

    The next IEMs to test hiss with were my UE Triple.Fi 10 and my UERM customs, two IEMs that are also very hiss-revealing, but not such extreme divas as the SE846.
    When playback was paused, there was only very little ground noise audible in my quiet listening environment. and as soon as I started music playback, hiss was gone immediately even at low listening levels. That’s how it should be.

    As expected, there was no hiss at all with the Audeze and Superlux.

    Resolution, Precision, Stage:

    TCM Filter:

    First of all, I plugged my cheap Superlux HD681 into the Geek Out IEM 100.
    The first thing that caught my ear was that the Superlux, whose instrument separation is rather on the average side, now gained precision in terms of stage reproduction with an audibly better and more precise instrument separation. Lows also gained precision, impact and speed and the highs seemed more “tidied up”.

    Directly after, I plugged in my Shure SE846.
    The music’s first beats started and I got aware of the GO’s very precise instrument presentation and separation. The Shure, which is already an IEM with a precise soundstage presentation (though its stage is rather on the smaller side in comparison to other high-end IEMs) got an even more precise soundstage with better expansion in depth, including better layering and separation.
    Instrument separation in general was improved; single instruments and tonal elements were precisely separated from each other.
    Another striking thing was how dry the bass was presented and with what amount of precision and impact it hit. The whole low range was dry, precise and fast; the Geek Out IEM 100’s output lacked any signs of softness or sponginess.
    Furthermore, I noticed that the highs were clean, dry and exactly to the point.

    The Triple.Fi 10 which is an IEM without any real spatial depth really showed some small signs of layering when I connected it to the GO.

    The UERM’s tight and precise bass and its brilliant spaciousness and precise layering were enhanced by the GO; treble was fast and clean without sharpness.

    The gain of sonic quality was especially obvious in a tighter bass response with faster impact and a better layering and instrument separation when I connected my LCD-X to the Geek Out.

    FRM Filter:

    The biggest sonic difference between the TCM and FRM filter from what I perceive is that the sound is “smoother” with the FRM filter, without losing resolution or details.
    Treble and sibilance lose sharpness and sound both smoother and more analogue, but also a bit “dirtier” and slightly less precise and to the point than with the TCM filter.
    With bad and old recordings that often tend to have shrill and distorting highs, overall listening was more pleasant with the FRM filter, though the difference is comparatively small.

    Of course, the Geek Out doesn’t replace good headphones, which have, beside recording quality, the biggest influence on sound, but it supports their strengths and delivers a dry bass, gorgeous and three-dimensional stage reproduction and a treble that is right to the point.
    Furthermore, its sound is everything but lifeless and digital, but analogue in a very positive sense without any coloration.


    Does the Geek Out IEM 100 even have flaws then?
    Besides the somewhat rickety buttons, its only other flaw I could find is the quite huge generation of heat due to its Class A amplification. Heat is effectively derived through the aluminium enclosure; temperatures around 70°C are quite normal, according to the manual.
    Though, after disconnecting the GO from the computer, it cools down pretty quick.


    With the Geek Out IEM 100, Light Harmonic/LH Labs really have developed an audiophile sounding little USB DAC-Amp that is not more than twice the width of a regular USB stick.
    Its output impedance is even perfect for critical IEMs with multiple BA transducers; hiss is on a very low level even with IEMs that have got a high sensitivity.
    Sure, there is minor criticism, but it is only limited to the aluminium enclosure that gets quite hot during use (that’s the price one has to pay for Class A amplification) and the somewhat rickety buttons, but the excellent sound and the extremely fair price point more than compensate these very minor flaws.
    Of course, it does not replace good headphones (there is no device that ever will either), but it really does support their strengths and offers a very clean and valuable audio playback.

    Well done, guys!
      mgunin likes this.


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