When it comes to headphone amplifiers, TOPPING's A70 Pro and A90D models stand out in the market. Both models are high-powered, packed with features, and designed to deliver stunning sound quality. However, each has unique characteristics that set it apart. Let's examine these in detail.


The T'ang-ku-la Module: TOPPING A70 Pro's Standout Feature

The TOPPING A70 Pro ($499) is equipped with the new T'ang-ku-la Module. Named after a mountain so high that even an eagle cannot fly over, it symbolizes the amplifier's superior performance. This module incorporates a new three-stage feedback circuit that minimizes noise and high-frequency distortion, pushing the dynamic range to an impressive 147dB.

The A70 Pro also benefits from an ultra-low noise input stage that enhances the balanced input noise performance and increases input impedance to 20kΩ. This development ensures better compatibility with a range of devices.


Power in Discretion: The TOPPING A90D

The TOPPING A90D ($599), on the other hand, stands out with its fully discrete NFCA modules. This design results in unparalleled distortion and noise performance. The A90D also boasts several user-friendly enhancements, including an R2R relay volume control, a remote control, and a ground loop noise terminator switch.

Specifications: A Closer Look

Output power: A70 Pro

Both models offer exceptional specifications, but there are noteworthy differences. The A70 Pro, for example, delivers a maximum output power of 17000mW x 2, while the A90D's max output power reaches 9800mW x 2. This could influence your choice if output power is a critical consideration.

SNR: A70 Pro

In terms of SNR (Signal-to-Noise Ratio), the A70 Pro has an edge with a max SNR of 147dB, compared to the A90D's 145dB. A higher SNR indicates a cleaner, more precise sound. The A70 Pro also leads in dynamic range, matching its SNR at 147dB.

THD+N: Tied

However, both amplifiers are equal when it comes to THD+N (Total Harmonic Distortion + Noise), with both offering a THD+N of <0.00005%. Lower THD+N values equate to less distortion and a more accurate representation of the original audio.

Gain range: A70 Pro

Both amplifiers also offer two gain settings, but the A70 Pro's gain range (6dB in low gain, 19.8dB in high gain) is wider than the A90D's, which may provide greater versatility.

User Experience and Additional Features

UI: Subjective

Both models excel in terms of user experience. The A70 Pro offers a vibrant Aurora UI with a full-color screen and three touch buttons, while the A90D provides a simpler screen-less interface that some users may prefer.

12V Trigger: Tied

Both models also feature a 12V trigger interface, allowing them to be turned on and off synchronously with other devices equipped with a 12V trigger interface. This feature is a notable enhancement in terms of convenience and seamless operation.

Ground loop noise terminator: Tied

Moreover, both the A70 Pro and the A90D have a ground loop noise terminator switch and relay volume control for precise volume adjustment.


In conclusion, while the A70 Pro boasts higher output power and a slightly better SNR, the A90D excels with its discrete NFCA modules. Your choice between the two would ultimately hinge on your specific needs and preferences.