The device is in great operating condition with minimal signs of use for its age Discontinued but still upgradable Info from the site: USB line interference form dirty computer side always affect DAC performance. MP-D2 introduces innovative isolation technology to completely isolate between the dirty PC side and the clean DAC side, so it gives you the most pure USB PC-HIFI performance you have never experienced before. Power Supply 150W toroidal transformer for analog section. Additional 80W toroidal transformer for digital sections. They provide more than 6 times power pool redundancy to support to most critical surge current requirement. They are magnet shielded in the compartment underneath the motherboard. The most advanced lowest noise LDO regulators are employed. In addition, more than 50000uf of total filtering caps are onboard. All of these deliver the highest standard of power performance once found only in leading edge lab equipment. Technology MP-D2 is powered by latest XMOS U8 asynchronous USB chip and 2x AKM flagship VERITA AK4490 32bit DAC chips. XMOS Incorporated with three super high precision TCXO clocks deliver lowest jitter performance. Dual AK4490 in mono block configuration and custom voltage setting deliver 126db dynamic range performance. MP-D2 supports PCM up to 384Khz and DSD64, DSD128, and DSD256. Analog Output Stage - Tubes and Caps MP-D2 output stage only employs vacuum tubes. No solid state component, zero feedback and fully balanced circuitry. Tube rectification circuit delivers more analog sounding. The unique design of the MP-D2 supports multiple series of signal and rectifier tubes. It is also the first one in the world offering user changeable output stage coupling capacitors. No soldering is required! You owns the freedom to select the tubes and caps. You have never felt anything like it. Exterior The full chassis is built with aluminum alloy. Even the legs, knobs, tube protection rings and buttons are made with solid aluminum alloy. The simplicity of front panel design allows you get used to it in minutes. How it sound in General? Extremely dynamic, vivid and detailed sounding. Excellent bass weight and extension. Smooth, liquid and airy mid-range and high. Deep and wide sound-stage. Features and Specs Asynchronous transfer mode for dual USB input. DSD and PCM input over USB. USB and clock isolation. Short delay sharp roll off 50Khz digital filter. AES, Optical, Coaxial digital inputs. Zero-feedback, fully-balanced full tube circuitry. Selectable low gain and high gain output. Power-line RFI filter. Pre-amp output feature (10V Max) Tube Rectification Signal tubes - 6.3V series: 6N11 (stock), 6H6, 6H30, E88CC, E188CC6922, 6DJ8. 12.6V series: 12AU7, 12BH7, E80CC. Rectifier tubes - 6.3V series: 6Z5P (stock), 6X5. 5V series: 5R4, 5AR4, 5U4G, 5Y3, GZ34 Frequency Response DC to 50khz DR / SN 126 dB Output Level 6 volts balanced XLR, 3 volts single-ended RCA Input 2x USB PCM 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz, (384kHz only in Mac and Linux). DSD64, DSD128, (DSD256 AK4490 & AK4497) 1x Coax, 1x AES, 1x Optical PCM 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz Dimensions W 34.5cm x D 38cm x H 15cm Gross Weight 12.5 kg