FiiO GIGAS 1 Desktop Headphone Amplifier

The FiiO Jade Audio GIGAS 1 is a compact desktop headphone amplifier with giant power: GIGAS is Greek for “giant”. FiiO created the GIGAS series after launching its JT7 planar headphones, which need a lot of power, because sources with enough drive were usually expensive. The GIGAS 1 fixes that at an affordable price: a discrete Class AB circuit with onsemi transistors delivers up to 4,600mW per channel from its 4.4mm balanced output, enough for entry-level planar headphones from FiiO and other brands, full-size headphones and IEMs. It has 3.5mm and RCA inputs, 3.5mm and 4.4mm outputs, two gain levels and runs from USB-C at 5V or PD 12V.

Discrete Class AB current amplification

The amplifier is built from discrete parts: op-amps for voltage gain followed by transistor current amplification, using the classic onsemi MJE243G and MJE253G pair, for high-current, low-impedance output. FiiO describes the sound as smooth, natural and melodious, and it drives full-size headphones and IEMs with ease.

The headphone amp uses the same fully balanced architecture as FiiO’s K17: a phase inverter, then dual op-amps and eight transistors for current amplification. Because the balanced output doesn’t use ground as a reference, interference drops and channel separation rises from 75dB (3.5mm) to 95dB (4.4mm), and the higher voltage swing gives more power for high-impedance or low-sensitivity headphones.

Power for planars and high-impedance headphones

Powered by a PD 12V adapter on high gain, the GIGAS 1 delivers up to 4,600mW + 4,600mW balanced. Into 300Ω it still manages 740mW per channel with a 42V peak-to-peak swing (90mW on 5V power), so it can drive most high-impedance headphones too. Output impedance is 1Ω or less (3.5mm) and 1.5Ω or less (4.4mm). With IEMs, if you are worried about too much power, use 5V power or low gain for a lower noise floor.

Two outputs, with mic passthrough

The front has a 3.5mm single-ended and a 4.4mm balanced headphone output, which can be used at the same time. The 3.5mm socket passes through a CTIA headset microphone, for game chat, calls and multimedia.

Two inputs for any source

At the back, 3.5mm and RCA analogue inputs connect players, phones, computers, Bluetooth receivers, DACs and CD players (don’t use both at once, or the signals will mix). The GIGAS 1 is a pure analogue amplifier with no DAC of its own, so FiiO developed TRUST and LINK cables to connect it, including the TRUST LT-3.5 Type-C to 3.5mm decoding cable for phones and computers, and RCA cables such as the TRUST LR-RCA6. A USB dongle DAC connects with a simple 3.5mm cable.

Why single-ended inputs?

Volume is set by a purely analogue dual-gang potentiometer. A balanced input would need a far more expensive four-gang pot, so FiiO kept the inputs single-ended while making the amplifier itself balanced; balanced output and separation are still substantially better than single-ended, and the price stays low. At very low volume a slight left-right imbalance is normal for a potentiometer and disappears at normal listening levels.

Two gains, 5V or 12V power

Low gain suits sensitive headphones, high gain low-sensitivity or high-impedance ones. The maximum power is the same in both, because the amplifier and power supply don’t change: high gain simply reaches it with a smaller input signal, while low gain gives less output and a lower noise floor for the same input. Power comes in over USB-C: 5V works, but FiiO recommends a PD 12V adapter and USB-C cable, which gives clearly more power and better sound. As a Class AB amplifier, it gets warm or even hot in normal use.

Good to know

• No DAC or Bluetooth inside. For wireless, pair it with FiiO’s BR15 R2R or BTA30 Pro.
• Made for headphones like the Jade Audio JT7 planar, and most other over-ear headphones.
• Want a DAC built in? FiiO’s K17 shares the GIGAS 1’s balanced amp architecture.
• In the box: GIGAS 1, USB-C power cable and documentation.