SDG #060 FX-Audio FX-98S Pro 16-bit USB DAC and Headphone Amplifier - PCM2704

The FX-Audio FX-98S Pro sits in the crowded budget bracket of USB sound cards that promise to rescue your headphones from noisy motherboard audio. It is built around the venerable PCM2704, a 16-bit, 48kHz USB Audio Class 1 chip that has been around for years and needs no drivers on Windows, macOS or Linux. That immediately sets expectations: this is not a high resolution device, and any marketing that hints otherwise is stretching the truth. What matters instead is whether the analogue stages around the DAC are clean enough, and whether the headphone amplifier can actually drive a real load.

The review works through the physical product first, looking at the enclosure, connectors and the internal layout, then examines the board to confirm what silicon is actually fitted and how the output stage and power supply are arranged. USB bus powered designs like this live or die on how well they reject noise coming down the 5V rail from the host PC, so decoupling, regulation and grounding choices are worth scrutinising rather than taking the specification sheet at face value.

Listening impressions are backed by bench work covering output level, noise floor and behaviour into headphone impedances, which is where cheap amplifier stages often reveal their limits through distortion or a collapsing bass response with low impedance cans.

For a buyer, the practical question is value. If your laptop or desktop has audibly poor onboard audio, a PCM2704 based box like the FX-98S Pro can be a cheap and genuinely useful upgrade. If you already have decent onboard audio or want 24-bit playback and high impedance drive capability, the money is better spent elsewhere.