The Fosi Audio P4 was inspired by user feedback collected after the launch of the V3 stereo amplifier. It combines source selection, volume control, and tone adjustment in a single compact control hub.

The 2.0-channel P4 is designed for stereo systems that require multiple analog audio sources to be connected to an amplifier, powered speakers, or another compatible audio device.

The three RCA inputs allow multiple line-level analog audio sources to be connected simultaneously. The P4 can be used with CD players, network streamers, DACs, and turntables with a built-in phono preamplifier.

Quick input switching allows the P4 to simplify the operation of multi-component audio systems by serving as a compact analog control hub.

The Fosi Audio P4 uses a high-precision motorized analog potentiometer for volume adjustment. It provides smooth and consistent control, while the circuit design aims to reduce noise and distortion.

Thanks to its motorized operation, the volume can also be adjusted conveniently with the included remote control while retaining analog volume control.

The three-level gain adjustment allows the P4 to be matched with audio sources featuring different output levels. Selecting the appropriate gain level supports an optimal volume range and effective signal handling.

The bass and treble controls allow the sound character to be tailored to the audio system, room, and personal preference. The tone bypass function bypasses the tone control circuit, providing a more direct signal path without tone correction.

The included remote control lets you adjust the volume, select the desired input source, and control the tone from a distance, so there is no need to reach for the preamplifier whenever you want to use its essential functions.

The RCA output and pre-out allow the P4 to be integrated easily into various home audio systems. It can be connected to a power amplifier, powered speakers, or another audio device that accepts a line-level analog signal.

The pre-out can also be used to connect a powered subwoofer or powered speakers, allowing the system to be expanded with additional components later. These output options make it easy to use the P4 in both compact and more complex stereo systems.

With a signal-to-noise ratio of at least 110 dB, a dynamic range of at least 110 dB, and THD+N of no more than 0.003%, the Fosi Audio P4 supports clean and accurate analog signal transmission. Its noise floor of no more than 9 µV helps preserve quiet musical details.

The 20 Hz to 20 kHz frequency response with ±0.1 dB deviation provides consistent signal handling across the audible frequency range. Channel separation of at least 105 dB supports effective separation between the left and right channels.

The P4’s sleek, minimalist enclosure takes up little space, making it easy to accommodate in smaller desktop audio systems. Its intuitive controls provide quick access to volume, source, and tone settings.

The solid design resists electromagnetic interference, supporting reliable long-term operation. Its compact size and understated appearance allow the P4 to blend seamlessly with a variety of audio components.