Topping's excellent LA90 model using discrete circuits. A high-performance Class AB amplifier that delivers an amazing listening experience, the NFCA headphone amplifier delivers extremely clear and accurate sound reproduction. The Topping LA90 uses a conventional integrated circuit (IC) as the main amplifier component, while the Topping LA90 Discrete uses discrete components such as transistors, resistors and capacitors for amplification. Discrete components generally offer better sound quality by allowing more precise tuning and control of the amplification process.