With Groove, the high-quality audio technology from the world's most renowned recording studios is available on your laptop. Connect Groove to your computer's USB port and your headphones or active speakers to Groove's audio output. There's always plenty of power available at Groove's output regardless of impedance, while Apogee's Constant Current
Features + USB 2.0 connection for Mac and PC + 24 bit / 192 kHz audio + ESS Sabre D/A converter + Optimizes your listening experience with iTunes, Tidal, Spotify, Pandora and other music platforms + Constant Current
Package contents: + Groove + USB cable (30 cm) + Carrying case + Product brochure (quick start guide, warranty information) + Software download guide and full documentation + Dimensions (L x W x H)95 x 30 x 16 mm + weight 45.35 g + Power supply 5 V, 500 mA, USB
SYSTEM REQUIREMENTS
+ Windows: Computer: Manufactured after January 2006 + Intel Core 2 @ 1.6 GHz or equivalent AMD processor, 1 GB RAM + Win7,8,8.1 (32 and 64 bit) + Mac OS: + Computer: Intel Mac with 1.5 GHz or faster, Min. 2 GB RAM, 4 GB recommended + OS: 10.8 or newer
Transparant, clean and powerfull.
Feeding two DT-990 Pro, 250 Ohm without amplifier is no problem at all. I used it with Windows 7U and (Debian/Ubuntu) Linux. With Linux, no driver installation is required.