Designed for the purest sound, entirely within the analogue domain, the Fosi Audio P4 is a mini pre-amp with a big impact on your system’s sound.

Mini pre-amp
Ideal for a high quality desktop audio system, the Fosi Audio P4 is a mini pre-amp with sophisticated sound. Precision components include replaceable op-amps, letting you upgrade the sound to suit your preferences. For the best match with your power amp, there are three output gain settings.

Analogue-only inputs
For the best possible sound from your sources, this pre-amp focuses on analogue inputs only. For ideal audio from your digital sources, simply input via a separate DAC (Digital to Analogue Convertor).

Smooth, adjustable control
With its motorised, analogue volume control, the P4 delivers smooth and precise volume adjustment, entirely in the analogue domain. Separate bass and treble controls let you tweak the sound to suit your tastes. For the purest audio signal, a switch at the rear clicks a bypass into place, giving you the least resistance and the most detail possible.

Upgradeable sound
Although impressive for its price, straight from the box, the P4’s sound quality can be further enhanced via a DIY component upgrade. Replacing the op-amps with optional (at extra cost) SparkoS Labs devices gives more detailed, higher resolution sound. The upgrade is solder-free, with the components simply pushing into place.

Small size means hi-fi quality sound in more places than ever
With a footprint that’s little larger than a chunky smartphone, if there’s space to put your smartphone down, there’s space for this pre-amp. Perfect for crowded desktops and bookshelves, the P4 gives you the potential for true hi-fi sound in more places than ever.

Experience the quality of true hi-fi separates, in miniature, with the Fosi Audio P4 mini pre-amp.