Topping's A90D Discrete Headphone Amp is a High Performance Fully Discrete Balanced Headphone Amplifier. The A90 Discrete uses fully discrete components to redesign the NFCA (Nested Feedback Composite Amplifier) module.

4 built in NFCA discrete modules which each uses 39 transistors built up for a fully balanced structure. The optimised voltage current hybrid feedback architecture along with UHGF (Ultra High Gain Feedback) technology provides excellent Dc and AC performance. Benefiting from the new design, the output capability is stronger than ever, which allows the amplifier driving low impedance headphones with ease. The paralleled ultra low noise precision matched transistors in the design ensure the unparalleled distortion and noise performance.

If ground loops are encountered then the A90D has you covered with a switch to lift the ground from the equipment but it is set to GND when in normal use, it has also incorporated a 12volt trigger to trigger any external products like amplifiers

The A90D has three headphones outputs for all your headphone connection needs in 4 pin XLR Balanced, 4.4 mm Balanced and 6.3 mm single ended, the A90D also has two different gains settings to apart to various sensitive headphones Low Gain 0db and High Gain 9.5db for single ended and Low Gain 6db and High Gain 15.5db for balanced output with these settings we are sure you will find one that will be right for your inear or full size headphones.

The Topping A90D can also be used as a preamp and when it is in preamp mode the XLR or RCA outputs can be use, the single end has a impedance of 20ohms and the balanced XLR 40 ohms which are widely used you ca also add the EXT90 to give you more inputs as a preamp if needed.