So I saw this for real cheaps and had to grab it. Firmware has been flashed to V1.5 with the TCM(which I typoed TRM) and FRM filters. Sound wise, I'm getting the feeling that this might be the 9023 implementation and easily competes with the Herus/Concero maybe though I need a direct comparison to be sure. Sounds fairly consistent sounding with changing sampling rates and across different computers once fully warmed up which is a HUGE plus for me.

My impressions of the device as a DAC are the same as the rest in that the TCM filter sounds full bodied and the FRM filter makes piano strikes sound weird. Maybe one mode might be better than the other depending on the music you listen to.

The bad? The driver package is pretty bad, device does not get recognised sometimes on my Win 7 rig which requires me to remove and reinstall drivers in order for device to be recognised as a soundcard.

Also the device requires warm up time to get hot before any listening or evaluation of its capabilities is done. The clocks do take a while to settle and in FRM filter mode, I found it to distort and clip with a full scale 19.1khz tones when the device is cold. Jitter also looks bad when the device is cold as 16 bit and 24 bit spectrum measurements are swamped with noise, it disappears when warmed up. When cold, the device is Sabre done wrong(or normal lol) with some harshness out of box.

Measurements wise, the Geek Out pulps the ODAC and the competition at its price point. The TCM filter measures worse in most areas but looks better in some places than the FRM filter so we can see some trade offs and compromises with filter choices.

Rig:
Acer Win8 Laptop-> ASIO -> GO100-> Short 3.5mm to RCA cable-> EMU0404 via RCA to XLR adapters-> Fujitsu Laptop
Software: Foobar with RAM buffering, WaveGene, WaveSpectra, ARTA

Note: Typoed Time Coherent Mode(TCM) as TRM.
DISCLAIMERS: Not science, YMMV. Also do take note of the rising noise with wide bandwidth measurements of the 0404.

The Geek IEM as of firmware 1.5 which you can flash from the Geek website using the tools from the driver package, has a choice of a fast rolloff minimum phase filter which is the so called TCM filter and a slow rolloff symmetrical linear phase filter which they called its FRM filter. As you can see, the TCM filter has no pre ringing but more post ringing.




FRM reconstruction filter measurements, this test is carried with a 44.1khz sample rate and is based on the DAC testing methods use by John Atkinson at Stereophile . A spectrum of white noise is overlayed with a separate full scale 19.1khz tone. Due to the tone's closeness to the bandwidth of the sampling rate, it stresses out the DAC's aliasing filter to produce a 25khz aliasing product.

At 0dbFS, there seems to be problems with the FRM filter thus we see a lot of spuraie, this measurement was taken when the device is warmed out. When cold, the distortion reaches pretty damn high.  Also seen is the filter's performance with a -3dbFS tone. The slow rolloff till 30khz means that the aliasing image is not rejected at all. Note the levels of the tone which means that with this filter, there is some rolloff in the highs.




Same test but with the TCM filter. With a steep rolloff, much of the aliasing image at 25khz is rejected. Distortion profile looks almost like the ODAC's but better.




THD, FRM performs much better, observe the distortion profiles though, also the typical Sabre spuraie .




Copied from below: -90dbFS 1khz Test, this test reveals the low level resolution of the GO100, typically with Sabre devices I have seen so far, whether it be the DX90, ODAC or Herus, there would typically be some spuraie at low levels. This is where the GO pounds the competition, essentially free of any pickets. Only thing is the noise levels are higher than the rest which can be seen in the 24 bit waveform.


24 bit blue, 16 bit red.

-90dbFS sinewaves, 16 bit is the one with 3 modulation steps.

SMPTE and DIN Intermodulation Distortion, FRM mode aces this test, though the TCM mode does not perform too shabbily





CCIF high frequency twin tone tests, again FRM puts out better numbers but we can see some extra spuraie with the FRM filter, probably due to the aliasing image? EDIT: On another note, it came to me that this is FANTASTIC intermodulation distortion performance. TONs better than any device I have tested so far except the EMU0404 DAC section.




Lastly, jitter. Before warm up of the GO100, there is plenty of noise and it looks kinda awful for a modern DAC. Even after full warmup though, skirting of the base can still be seen indicating some low frequency jitter. Not bad but not that good either.


Dunn Jtest with 48khz sampling rate, 24 bit data blue, 16 bit red.


To wrap up, the Geek offers features well above its price point with good engineering chops to back it up as well. If that could be backed by better driver support, it would be a good product.

ADDED 18/12/2014: GEEK internal pics http://www.changstar.com/index.php/topic,1965.msg54628.html#msg54628