The CLASS A is a desktop headphone amplifier and preamplifier for listeners who want the warm, natural character of a fully discrete Class A transistor circuit, with enough power to drive demanding planar and high-impedance headphones from its balanced outputs. It is the headphone amplifier at the centre of FiiO's retro-styled desktop system, sharing its chassis size and design language with the DP11 CD player and WARMER R2R DAC, and it accepts balanced and single-ended line inputs so it can sit after almost any DAC or source.
Fully Discrete Class A Design
The amplifier is built from individual audio transistors with carefully selected resistors and capacitors, and each channel's components are matched and hand tuned, with the quiescent current of every unit calibrated manually. The amplifier pairs sixteen Toshiba twin audio transistors with eight Sanken audio transistors: FiiO chose the Toshiba parts for a warm, smooth presentation with a relaxed low end and engaging vocals, and the Sanken parts for speed, dynamics and control in large-scale orchestral and rock music. Around them sit eight WIMA film capacitors, twenty ELNA audio capacitors and twenty high-precision MELF resistors. A DC servo circuit continuously monitors the output and holds DC offset at zero, protecting your headphones and keeping the bass clean and controlled.
Power Supply
A Class A circuit draws a high quiescent current all the time, so the CLASS A uses a custom 60W toroidal transformer purpose built for the task, with a discrete regulated power supply and a split supply design that feeds each amplification stage independently. A 20,000uF reservoir of Nichicon audio-grade filter capacitors smooths the rectified supply, suppressing mains ripple for a quiet background, and stores the energy needed for sudden dynamic peaks so drums and orchestral climaxes stay tight and composed.
Output and Flexibility
The fully balanced differential architecture delivers up to 4000mW per channel into 32 Ohms from the balanced outputs, with a quoted output impedance below 1.5 Ohms balanced and below 1 Ohm single-ended, so it suits sensitive in-ear monitors as well as full-size headphones. Five gain levels (Low, Medium, High, Super High and Ultra High) make it straightforward to match the amplifier to any headphone, and independent bass and treble controls offer plus or minus 10dB of adjustment for tailoring the sound to your preference.
Connectivity
The front panel carries 6.35mm, 4.4mm balanced and 4-pin XLR balanced headphone outputs. On the rear are four line inputs (RCA, 3.5mm, 4.4mm balanced and XLR balanced) and two line outputs (RCA and XLR balanced), allowing the CLASS A to act as a preamplifier feeding a power amplifier or active speakers. Bidirectional 12V trigger in and out sockets let it power up and down in step with a source or a downstream amplifier, and a USB-C port is provided for firmware updates. A full set of protection circuits covers DC output, power input overcurrent, overvoltage, output overload, and both headphone amplifier and transformer temperature.
Available in two finishes; this one is Silver.
