Have had these for quite a while now. Thanks Raif!
Keep in mind that when describing how an Amp/DAC sounds, to me it is not always at the same level as with headphones. In most cases differences are more subtle... sometimes. With that in mind, these are IMO warm yet very detailed. I think it complements well headphones such as the HD600. It's a pretty powerful little gadget, and it gets a bit warm...
The Geek (1000 mW) is also a pretty practical device and it indeed handles all the way to 192 kpbs through it's ASIO driver. I feel it can render dynamics pretty well. I found this little amp quite engaging indeed.
What I did not like AT ALL is the volume control. HORRIBLE. The volume setting needs to be saved somewhere inside the device. ALWAYS make sure the volume is turn down before playing anything through. Default is full powa.
As far as measurements is concerned, take them with a grain of salt. I'm not using an Audio Precision or a Prism Sound or a whatevers... Just a set of laptops and good 'ol REW. Results I get seem a little worse than what the LightHarmonic guys get, but not bad at all IMO.
Test were done with a 33 ohm load. The Geek is able to deliver 4 Vrms into 33 ohms, which translate into about ~500 mW. I'm confident that with a 16 ohm load (if current is not limited by the USB source) the Geek will deliver 1W... This is about 250 mA, and I'm definitively not confident that the Geek will deliver these 1Ws in "Class A" mode.
Here are the 1 kHz THD plots under different output power considerations and using 192 kHz option in the Geek (Focusrite 2i2 capture is set to 96 kHz which is the highest it can do):
NOTE: Please ignore the y-scale, as the dBFS are off by about 5 dB. However, the distortion % are IMO accurate. Full scale to me is 4 Vrms (relative to the Geek), but the 2i2 inputs are not calibrated to that. The title of the plots specify what I think is the actual dBFS.1 kHz THD (-20 dBFS)1 kHz THD (-10 dBFS)1 kHz THD (1 Vrms)
Same situation, but Geek is set to 44.1 kHz1 kHz THD (1 Vrms)
The following are the 500 Hz THD numbers for 44.1 kHz and 192 kHz Geek settings @ 1 Vrms500 Hz THD (192 kHz)500 Hz THD (44.1kHz)