The Topping A90D is made using fully discrete components as a redesign of the NFCA (Nested Feedeback Composit Amplifier) module. Featuring 4 built-in NFCA-Discrete modules, each using 39 transistors to build up a fully balanced structure. The optimized Voltage Current hybrid feedback architecture together with UHGF (Ultra High Gain Feedback) technology both offer incredible DC and AC performance. Thanks to the new design, the output capability is stronger than ever, which enables the amp to drive low impedance headphones even more effortlessly. The paralleled ultra low noise precision matched transistors built-in ensure the unparalleled distortion and noise performance.