Fostex HP-A3mk2 vs Topping A70 Pro: DAC Amp Comparison
By Addicted To Audio - Home Audio Electronics & Accessories | Published: 2026-10-21
Category: Comparisons
Compare the Fostex HP-A3mk2 and Topping A70 Pro headphone amplifiers and DACs. Find out which balanced amp suits your desktop setup based on power, features, and budget.
Quick answer
Choose the Topping A70 Pro if you need extreme balanced power and ultra-low noise for demanding headphones. Pick the Fostex HP-A3mk2 if you want a compact, bus-powered USB DAC/amp with a built-in ESS DAC for simple desktop use.
Power and amplification approach
The Topping A70 Pro is a dedicated balanced headphone amplifier built around the T'ang-ku-la amplifier module, which uses a new three-stage feedback circuit to reduce noise and high-frequency distortion. Its dynamic range reaches 147dB, making it ideal for revealing fine details in high-impedance or planar magnetic headphones.
The Fostex HP-A3mk2 is a USB DAC with a headphone output, designed for convenience. It runs on USB bus power and uses the ES9016K2M DAC chip from ESS Technology. While it delivers clean sound for efficient headphones, it lacks the raw balanced power of the A70 Pro.
DAC functionality and connectivity
The Fostex HP-A3mk2 includes a built-in DAC that accepts USB audio and optical digital signals, converting them to analog for line or headphone output. It works with standard USB Audio 2.0 drivers on Windows and Mac, so setup is quick.
The Topping A70 Pro is purely an amplifier—it has no internal DAC. You will need to pair it with a separate DAC source. This gives you flexibility to choose your own DAC but adds cost and complexity.
Heat and form factor
The Topping A70 Pro's high-performance module generates noticeable heat, which is a trade-off for its class-leading noise and distortion figures. Ensure adequate ventilation in your setup.
The Fostex HP-A3mk2 stays cool thanks to its low-power USB bus operation, making it easy to tuck into tight desktop spaces without worrying about airflow.
Trade-offs at a glance
- Power and headroom: The Topping A70 Pro delivers far more balanced power and lower noise, ideal for demanding headphones. The Fostex HP-A3mk2 is limited to moderate volume levels with efficient headphones.
- Built-in DAC: The Fostex HP-A3mk2 includes a capable ESS DAC and works as a standalone USB DAC/amp. The Topping A70 Pro requires a separate DAC, adding cost and setup steps. If you want an all-in-one, the Fostex saves space and money. If you already own a DAC, the Topping is a pure upgrade.
- Heat and portability: The Topping A70 Pro runs hot and needs ventilation. The Fostex HP-A3mk2 runs cool and is bus-powered, making it easy to move between desks or take on the go.
Product facts
- Topping A70 Pro Balanced Headphone Amplifier: All New T'ang-ku-la Amplifier Module uses a three-stage feedback circuit to reduce noise and high-frequency distortion, achieving 147dB dynamic range. This means extremely clean, detailed amplification for sensitive or high-end headphones, especially in balanced mode.
Topping A70 Pro Balanced Headphone Amplifier - Fostex HP-A3mk2 Headphone Amplifier & DAC: The HP-A3mk2 is a USB DAC that operates on USB bus power and uses the ES9016K2M DAC chip from ESS Technology. You get a complete DAC/amp solution that works right out of the box with a PC, without needing an external power supply or separate DAC.
Fostex HP-A3mk2 Headphone Amplifier & DAC
Which one fits you?
Best for
- Audiophiles with high-impedance or planar magnetic headphones who want maximum balanced power and ultra-low noise.
- Users who already own a separate DAC and want a dedicated reference-grade amplifier.
Not for
- Listeners who need a simple, all-in-one USB DAC/amp for a laptop or small desk.
- Budget-conscious buyers who prefer a compact, bus-powered solution without extra components.
