Audio-gd NFB-10SE Dac/Amp. This Dac/Preamp/Headphone amp combo unit is in perfect working condition with some minor cosmetic blemishes that do not affect the performance. This particular unit does require 240v input, but that can easily be fixed with a voltage step up converter.NFB means Non-FeedBack. NFB-10SE uses the latest high-end “Dual WM8741” which can support up to 32Bit/192KHz input. Similar to other WM8741 designs, NFB-10SE applies Non-feedback ACSS output stage. The “Dual WM8741” feeds to the ACSS output stage without any Operational Amplifier (OPA) so it can achieve very neutral sound. The ACSS technology is a non-feedback technology made with fully discrete amplifiers. Most people know that the global feedback design offers better specifications in measurements than non-feedback design. However, non-feedback design offers better sound for human ears, which is a drawback of the conventional circuits. But the ACSS technology opens a new era, it offers the least coloration sound which is very neutral with very low distortion and high linearity. It retains the dynamics, details and neutrality but does not sound bright or harsh. The output buffers are also non-feedback. In order to maintain low impedance, we applied a diamond output stage which is quite less colored than most conventional circuits. The analog stage does not use couple cap to avoid coloration. The 32bit/192KHz USB interface outputs an I2S signal to the “Dual WM8741”. NFB-10SE applies the WM8805 as the SPDIF interface; its sound characteristic is the same as the WM8741, which is detailed and smooth and supports up to 192KHz. The WM8805 has quite low jitter (50PS). Output impedance ?2 ohm Output Level ? Headphone output : 19V RMS (balanced , max) Preamp Variable output (balanced) : 10V RMS (max) Preamp Variable output (RCA) : 5V RMS (max) Fixed output (balanced): 5V RMS Fixed output (RCA): 2.5V RMS ACSS? 2MA+2MAHeadphone amp output power level (Only for headphone.) Balanced mode 9950MW / 25 ohm 5950MW / 50 ohm 3300MW / 100 ohm 1150MW / 300 ohm 590MW / 600 ohm ?Headphone amp output power level (Only for headphone.) Single-ended mode ?3300MW / 25 ohm 1650MW / 50 ohm 850MW / 100 ohm 300MW / 300 ohm 150MW / 600 ohmInput Sensitivity 0.5 Vp-p (75 Ohms, Coaxial) 19 dBm (Optical) USB1.1 USB2.0 (Full Speed, Class2) ?Frequency Response 20Hz - 20KHz ?-0.2DB? ? Support Operate Systems (USB) ? 44.1kHz to 192kHz?Support Sampling USB model : 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz Coaxial model: 44.1kHz, 48kHz, 88.2kHz, 96kHz, 192kHz Optical model: 44.1kHz, 48kHz, 88.2kHz, 96kHz ?Power Requirement 220-240V AC 50/60 Hz ?Power Consumption 17W ?Package Weight Approximately 5KG ? Dimensions ?W240 X L360 X H80 mm (Fully aluminum) Accessories AC power cord X1 ?