Fosi Audio P3 Tube Preamp Headphone Amplifier User Manual

: June 14, 2024
: Fosi Audio

Table of Contents

Fosi Audio P3 Tube Preamp Headphone Amplifier
Introduction
Specifications
Package Contents
Operation Guide
Precautions
Frequently Asked Questions
Warranty and Maintenance
About Us
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

Fosi Audio P3 Tube Preamp Headphone Amplifier

Introduction

Thank you for purchasing the Fosi Audio P3 Tube Preamplifier! The Fosi Audio P3 is a genuine tube preamp, with the tube working voltage reaching up to 54V. It features the QCC3031 Bluetooth chip, supporting aptX, aptX HD, and aptX LL audio formats, offering enhanced sound quality and as low as 60ms latency. The P3 comes with RCA out, AUX out, and a 3.5mm headphone jack, perfectly suited for your desktop use, delivering the ultimate auditory experience. The tubes are replaceable, adding to the fun of personalizing your setup. Combined with the glacier-colored light, it feels closer to nature. We believe that technology and nature can coexist harmoniously, and technological innovation can serve to enrich our lives. Fosi-Audio-P3-Tube-Preamp-Headphone-Amplifier-
fig-1

3.5mm headphone jack
Volume knob
Treble knob (±6dB)
Bass knob (±12dB)
Mode indicator light: RCA mode – steady red light, Bluetooth pairing mode – blue light flashing, Bluetooth connection successful – steady blue light
Power switch/mode selector
Bluetooth reset switch: Hold for 3 seconds to clear Bluetooth pairing
RCA input
RCA output
AUX output
DC 12V power in
Bluetooth antenna port
5654W tubes

Specifications

RMS Power

| ****

250mw @16Ω；150mw @32Ω；

32mw @250Ω；20mW @300Ω

---|---
Headphone Impedance| 16-300Ω
Input| Bluetooth，RCA

Output

| ****

RCA，3.5mm headphone jack， AUX Out

Package Contents

Fosi Audio P3 Tube Preamplifier × 1
12V/1.5A Power Supply × 1
5654W Vacuum Tube × 2
User Manual × 1

Operation Guide

Fosi-Audio-P3-Tube-Preamp-Headphone-Amplifier-fig-2

Switch to the OFF position, install the Bluetooth antenna, and then plug the tubes to the sockets. Ensure the pins align with the slots, and then turn the volume to the lowest setting;
Connect the included 12V/1.5A power supply;
Depending on your setup, plug your amplifier, powered speakers, or headphones into the P3’s RCA output, AUX output, or headphone jack;
If you opt for a wired connection, use an audio cable to connect your source device to the P3’s RCA input terminal;
Switch to either the RCA wired or BT Bluetooth wireless position;
When using Bluetooth, connect to Fosi Audio P3 on your source device;
Adjust the volume and treble/bass to an appropriate level, and you’re ready to enjoy your music.

Precautions

As a genuine tube preamplifier, please allow me 15 seconds to preheat the tubes after powering on, and then the sound can be output normally.
Avoid plugging and unplugging cables while the device is powered on to prevent abnormal noises. This can also easily damage the product.
If you need to replace the tubes, please do so when the tubes have cooled down to avoid burns or damage to the product.

Frequently Asked Questions

After connecting the product and turning it on, there’s no sound during playback.
Since the P3 is a tube preamp, the tubes require about 15 seconds to preheat before they can operate properly. If there is still no sound after 15 seconds, please check if the cables are connected correctly, if the tubes are properly plugged, and if the correct input mode is selected.

Why is the power indicator light very dim or constantly flashing after powering on?
A blinking blue light in Bluetooth mode indicates it’s awaiting a connection, and the light will remain steady blue once connected. A flashing power indicator light in RCA mode might suggest an insufficient power supply. Please ensure you’re using a power supply between 12V/1.5A and 12V/3A.

How are the headphone output, RCA output, and AUX output on the Fosi Audio P3 controlled?
By default, Fosi Audio P3 prioritizes headphone output, with RCA and AUX outputting simultaneously. This means both RCA and AUX will output signals at the same time; however, when a headphone is plugged in, the signal will switch to the headphone output, and there will be no signal on RCA and AUX outputs.

How do I clear the Bluetooth pairing record?
On the rear panel of the Fosi Audio P3, there’s an RST button. Press and hold for 3 seconds to clear Bluetooth pairing. If you’re in Bluetooth mode at this time, the indicator light will flash blue. If you have any further questions, please contact our support team at support@fosiaudio.com.

Warranty and Maintenance

Fosi Audio pledges to give a 24-month limited warranty and support from the date of purchase. If you encounter any problem when using our product, please contact our support team at support@fosiaudio.com.

About Us

Fosi Audio designs and builds innovative audio products with all your music in mind. Great sound, simple but elegant designs, high-quality components, and truly useful features are what Fosi Audio pursues. We sincerely hope you can get as much enjoyment from our products as we’ve had to create them!