Fosi Audio Box X4 MM Turntable Phono Preamplifier

A nice phono preamp

Have had this phono preamp for awhile. Produces a very good sound. I have a Denon DP-300F turntable. Sounds great when I am using my Grado 60s plugged in or I am sending it to my Yamaha RX-V800 receiver. Sound is better then using the pre-amp on the receiver. I listen to various Rock and Jazz genres.

Fosi Audio Box X4 Phono Preamp

A good preamp for turntable, but not good for Dac.

Warm sound but headphone preamp design could be better

This turntable (and “headphone”) preamp works very well for both of my vintage turntables (Sony PS-LX3 and Dual CS-616Q), producing clean and relatively warm sound. The bass and treble controls support fine tuning but I mostly leave them at the positions recommended by Fosi. Note that there is no center position detent. My only complaint is that it isn’t really a fully functional headphone preamp. It provides plenty of power for my Sennheiser cans but works directly only with the turntable as the audio input. If I want to listen with earphones for any other source I need to connect my Fosi ST20A PRO’s pre-out to the preamp line-in. That works okay but is needlessly kludgy.