Discover the Fosi Audio GR70: A Class-A Tube Headphone Amplifier & Preamp

At Fosi Audio, we believe that true HiFi experiences should be accessible without compromise. With that vision, we’re proud to introduce the Fosi Audio GR70 — a Class-A tube headphone amplifier and preamp designed to bring warmth, detail, and timeless aesthetics to your desktop audio setup.

A Blend of Style and Craftsmanship

The GR70 carries the signature Fosi Audio design language: all-aluminum construction, matte black finish, and a sleek, minimalist layout. The gentle glow of the vacuum tubes not only enhances the listening experience but also adds a touch of sophistication to any desk or HiFi corner. It’s a piece that looks as good as it sounds.

Pure Class-A Tube Sound

At its heart, the GR70 employs a two-stage tube amplification system:

• 5654 tubes for voltage amplification — ensuring rich musical detail and silky midrange.

• 6AC7 tubes for power amplification — delivering up to 3000mW output for demanding headphones.

This setup captures the essence of tube warmth while maintaining clarity and control, making it ideal for vocals, jazz, acoustic, and instrumental music lovers.

Versatility for Headphones and Speakers

Whether you’re lost in the intimacy of headphones or filling the room with your favorite records, the GR70 adapts effortlessly:

• Headphone Listening: A natural pairing for high-impedance and audiophile-grade headphones, delivering expansive soundstage and nuanced detail.

• Preamp with Powered Speakers: Perfect for vinyl setups or digital sources — pair it with a turntable and phono stage for a rich, analog-inspired experience.

Key Specs at a Glance

• Output Power: Up to 3000mW @ 32Ω

• Tube Setup: 5654 (voltage) + 6AC7 (power)

• Class-A Amplification: Pure, distortion-free sound

• Build: CNC-milled aluminum with matte finish

• Use Cases: Headphone amplifier or preamp for powered speakers

Designed for Real Listening

The GR70 doesn’t chase complexity — it focuses on what truly matters: authentic sound and user experience. With its compact footprint, elegant design, and powerful performance, the GR70 is your invitation to rediscover music with warmth and depth.