FiiO Class A Black

The FiiO CLASS A is a fully discrete Class A transistor headphone amplifier designed for desktop HiFi systems. Its fully balanced differential amplification architecture combines carefully selected audio components with a custom 60 W toroidal transformer and a high-capacity power supply to deliver high output power and controlled performance.

The amplifier uses Toshiba twin and complementary audio transistors alongside Sanken audio transistors, combining components selected for their different sonic characteristics. Each channel is precisely matched and manually tuned. The power supply features a split design with independent regulated power for multiple amplification stages and a 20,000 μF capacitor reservoir using Nichicon audio capacitors.

With balanced output power of up to 4,000 mW + 4,000 mW into 32 Ω, the CLASS A can drive a wide range of headphones. Five selectable gain levels accommodate different headphone requirements, while independent bass and treble controls provide ±10 dB adjustment. A DC servo circuit continuously monitors and corrects output DC offset to help protect connected headphones.

Connectivity includes four input options: 3.5 mm and RCA single-ended, plus 4.4 mm and XLR balanced. Headphone outputs are available through 6.35 mm, 4.4 mm and 4-pin XLR connectors. RCA and XLR preamplifier outputs allow connection to power amplifiers or active speakers, while bidirectional 12 V trigger connections enable coordinated power control with compatible equipment.

The CLASS A also incorporates protection against overheating, output overload, DC faults and input overvoltage. A USB-C port is provided for firmware updates, making the amplifier a versatile centrepiece for a desktop HiFi setup.

Features
Fully discrete Class A transistor headphone amplifier
Fully balanced differential amplification architecture
Custom 60 W toroidal transformer with electromagnetic shielding
20,000 μF Nichicon audio capacitor reservoir
Toshiba twin and complementary audio transistors
Sanken audio transistors
Up to 4,000 mW + 4,000 mW balanced output power into 32 Ω
Five selectable gain levels: Low, Medium, High, Super High and Ultra High
Independent bass and treble adjustment, ±10 dB
High-precision DC servo output control
3.5 mm and RCA single-ended inputs
4.4 mm and XLR balanced inputs
6.35 mm, 4.4 mm and 4-pin XLR headphone outputs
RCA single-ended and XLR balanced preamplifier outputs
Bidirectional 12 V trigger input and output
USB-C firmware update port
Thermal, overload, DC output and overvoltage protection

Specifications
Amplification class: Class A
Amplifier architecture: Fully discrete, fully balanced differential
Transformer: Custom 60 W toroidal transformer
Power supply capacitance: 20,000 μF
Balanced output power: 4,000 mW + 4,000 mW at 32 Ω
Tone adjustment: Bass ±10 dB, Treble ±10 dB
Gain settings: 5