








Fosi Audio GR70 Tube Headphone Amp
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Features
- Pure Tube Amplification
- Adjustable Impedance and bass & treble Control
- 2-in-1 Headphone Amp and Preamp
- Supports 16–300Ω Headphone Impedance
Pairs well with
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Fosi Audio GR70 Tube Headphone Amp
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
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Shipping Information
We offer free worldwide shipping, except for certain regions such as Ukraine and Russia, where our services are currently unavailable.
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Customer Support
WhatsApp: +8613716612254
support@fosiaudio.com
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FAQ’s
If you have any questions, please refer here: FAQs

Integrating Vintage Charm with Modern Precision
The GR70 is a two-in-one headphone amp and preamp. Easily integrate this tube preamp into your home audio system with its multiple headphone jacks and RCA input/output options.
- Input: RCA; Output: RCA, 6.35mm/3.5mm Headphone Output;
- Max Power Output: 300mW@32Ω; Power Input: DC 12V/3A;
- Headphone Impedance: Low Mode: 16Ω-120Ω, High Mode: 120Ω-300Ω;
Product details
Description
- 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
- Quad Tubes: 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
- 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
- Two-in-One: 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
- 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
What‘s in the box?
- GR70 Main Unit *1
- 6AC7 Vacuum Tubes *2
- 5654 Vacuum Tubes *2
- Tube Protection Covers *2
- 12V/3A Power Supply *1
- User Manual