Fosi Audio GR70 Class A Vacuum Tube Headphone Amplifier Preamp

Feature

1.Pure Tube-Amplification

The GR70 headphone tube amp combines vintage charm with modern tech, delivering authentic tube essence. Perfect for headphone enthusiasts, it pairs excellently with over-ear and in-ear headphones for superior audio

2.Replaceable Tubes for Custom Sound

Features two 5654W and two 6Ж4 vacuum tubes for two-stage amplification. The 5654W tubes boost voltage, while the 6Ж4 tubes handle power amplification. This setup delivers balanced, transparent, and textured sound.Users can swap tubes to explore different sound effects, adding playability and flexibility for personalized customization.

3.User-Friendly Design

This tube headphone amp preamplifier offers intuitive controls, including a large volume knob, dual-side ventilation holes, bass & treble controls, high and low impedance mode switching, making it versatile enough

4.Free Switching Impedance Mode

It supports low and high impedance modes switching to adapt 16Ω-300Ω headphones, and features 6.35mm/3.5mm headphone jacks on the front and RCA Input/Output on the rear for home audio HiFi system integration

5.Compact Yet Powerful:

Crafted with a CNC-machined aluminum alloy body, the GR70 is both durable and refined. Despite its compact size, it delivers up to 300mW power output and 1.2V RCA output with SNR ≥97dB—offering warm, clean, and dynamic sound

Model: GR70
Bass and Treble Adjustment: YES
Tubes: 6Ж4 ×2, 5654 ×2
Signal Input Mode: RCA
Output: 3.5mm headphone + 6.35mm headphone + RCA full-range signal output
Rated Output Power: 60mW
Input Voltage and Current: 12V 3A
Signal-to-Noise Ratio: ≥97dB
Frequency Response: 20Hz-20kHz (±1dB)
Dynamic Range: 97dB