Topping returns with the A90 Discrete, an improvement of the previous A90, this time equipped with discrete components. Both a headphone amplifier and a preamplifier, it incorporates a discrete NFCA amplifier stage capable of supporting most headphones on the market. Its careful design using many high-end components allows it to deliver a rich, clear and transparent sound.
Discrete NFCA amplifier
Topping's A90 Discrete features a Nested Feedback Composite Amplifier (NFCA) stage based on the use of discrete components. The four integrated discrete NFCA modules each use 39 transistors in a balanced design. The optimized hybrid voltage/current feedback architecture and Ultra High Gain Feedback (UHGF) technology provide excellent DC and AC performance. With this new design, the A90 Discrete benefits from high output power, allowing it to accompany both high-sensitivity headphones and high-impedance headphones effortlessly. Precisely matched ultra-low noise transistors connected in parallel ensure extremely low noise and distortion.
High output voltage and current
The Topping A90 Discrete offers both high output voltage and current. The former allows the amplifier to accompany high impedance headphones without difficulty, while the latter provides sufficient power for low sensitivity headphones.
Two gain settings
The unit also offers two different gain settings to accommodate an ever-growing array of headphones: low gain for high-sensitivity headphones, high gain for the most demanding headphones. Combined with a noise level of only 0.2µVrms, even the most sensitive IEMs will not suffer from any noise.
Elimination of mass loops
A ground loop can occur when several devices are used together. Therefore, the A90 Discrete provides a GND/LIFT switch to solve this problem. In normal use, if no sound fault occurs, the switch can be set to GND. Otherwise, if a ground loop is encountered, the switch should be set to LIFT.
In addition to its headphone amplifier section, the A90 Discrete includes a preamp circuit. In preamp mode, you get the same performance as in headphone amplifier mode. The single-ended 20Ω and balanced 40Ω outputs allow to accompany many amplifiers. Moreover the two modes can be used simultaneously and the remote control allows to access each function easily.
The A90 Discrete is equipped with a 12V trigger that can work as an active control (trigger output) or passive control (trigger input). Thus, the A90 Discrete can be switched on and off in full synchronization with other 12V triggered devices in your audio system.
Custom volume control
The Topping A90 Discrete uses an R2R volume control, composed of relays and resistors. It offers extremely precise control, perfect channel balance and excellent durability.
Possibility of extension
The A90 Discrete can be combined with the Topping EXT90, the latter offering a possibility of extension of the connectivity of the device. With the EXT90 connected, you will have four XLR inputs and two RCA inputs in total..
The Topping EXT90 is sold separately.