Amplifiers & Separates

Fosi Audiobox X2 Phono Pre-Amplifier Review

Vinyl is a rabbit hole that can cost you a lot of cash without much difference in sound. But what if you could add something that didn’t cost much and added real value to your system? Enter the Fosi Audiobox X2 Phono Pre-Amplifier. At $50 on Amazon, it won’t break the bank. But is it worth it? Let’s discuss. 

Who Should Get This?Who Should Pass?
Folks whose turntable or receiver doesn’t have a built-in phono stage, or;Those who are looking for a different “sound signature.”
Enthusiasts that find their built-in phono stage or cartridge has low output Enthusiasts who want an actual tube pre-amplifier 
Those who want to add a little “audiophile” touch without a massive outlay of cash Folks who need a pre-amplifier for a moving coil cartridge – the Fosi is for moving magnet only
People who have powered speakers and a turntable with no built-in pre-amplifier 

Under The Hood 

The Fosi Audiobox X2 Phono Pre-Amplifier is not a tube amp in the traditional sense. So, instead, it is a hybrid design that uses both digital processing and tubes in tandem to increase the gain from your turntable to your amp. The tubes amplify the incoming signal from your turntable, and the digital part controls the level of gain and the 3.5mm input signal. 


The Fosi Audiobox X2 Phono Pre-Amplifier has a simple layout. On the front are a 3.5mm input and a four-position on/off gain knob. It allows you to choose between 39, 42, and 45dB gain. The back features a power input, a push-style grounding lug, and a single pair of inputs and outputs. The top has a pair of B7G seven-pin sockets for the included vacuum tubes. The vacuum tubes are user-installed and replaceable, meaning you can quickly swap them with other compatible vacuum tubes. 


The setup of the Fosi Audiobox X2 Phono Pre-Amplifier is straightforward. Install the tubes on the top of the unit by aligning the pins and pushing them down firmly into the socket. Connect the power plug, grounding wire (if you have one), and then the inputs from your turntable and outputs to your amplifier. That’s it! 

If you have a built-in phono pre-amplifier on your amplifier, you must choose a different analog line input. 

Using the Fosi Audiobox X2 Phono Pre-Amplifier

Straightforward is the word of the day for the Fosi Audiobox X2 Phono Pre-Amplifier. Using the Fosi X2 is child’s play. Power up your equipment and choose the level of gain you want via the selector knob. Drop the needle and enjoy. 

You can switch between gain levels while the LP plays with no distortion or terrible sounds headed to your speakers. If you want to use the 3.5mm input, turn off the turntable and plug the 3.5mm cord from your device to the pre-amplifier. No other switches to set! 

How It Sounds 

In short, the Fosi Audiobox X2 Phono Pre-Amplifier doesn’t sound noticeably different from the built-in pre-amplifier in the turntable or the phono stage in my Onkyo. There is no additional “warmth” from the tube amps or other subjective nonsense. The sound is clear and distortion-free, and it provides significantly more gain than the built-in pre-amplifiers in my turntable and amplifier

So what does that mean? With the built-in preamps in my gear, I would need to set my amplifier to +10dB on the amplifier’s main volume to get about 75dB of volume out of my speakers. With the Fosi Audiobox X2 Pre-Amplifier and the gain at 36dB, the main volume on my amplifier was -12dB(ish) to get the same 75db out of my speakers. 

I also know that confirmation bias plays a huge part – I added a thing, so I hear a thing. To remove this, my editor told me to use my iPad to play digital music through the Fosi Audiobox X2 Pre-Amplifier and see if the preamp changed the sound. And with no surprise, there was no difference that I could hear from the preamps tubes. I played it through the preamp and my Bluetooth connection, and the only difference was the added volume from the gain adjustment on the X2s front panel. 

Our Take

So, should you get the Fosi Audiobox X2 Pre-Amplifier? As with most things in AV, that depends. If you don’t have a built-in pre-amplifier in your turntable or your amp, you will need a preamp. So, in that case, I have no issues recommending the Fosi Audiobox X2 Pre-Amplifier. It is inexpensive, has distortion-free sound, and adds a fair deal of gain for your turntable. If your built-in preamps aren’t loud enough for your taste, I readily recommend it. 

Same if you want to add a little “audiophile chic” to your setup, and you don’t want to spend a ton. At $50, I have spent far more on less, and it has proven to be a fantastic talking point while spinning tunes with my buddies and talking vinyl. While the tubes didn’t make an audible difference that I could hear, I like the way they look, and they don’t negatively impact the sound. 

But if you want to get that “warm” tube sound from the Fosi Audiobox X2 Pre-Amplifier, you need to look elsewhere. It doesn’t change the sound (aside from input gain). And that’s a good thing for a pre-amp. If I wanted something to change the sound, I’d have bought an EQ. For me, the Fosi Audiobox X2 is worth the money on looks alone. 

2 Comments on Fosi Audiobox X2 Phono Pre-Amplifier Review

    • Andrew Thomas

      Thanks for the heads up! I will get that fixed ASAP!

      Glad you enjoyed the article. Its a great little box and does exactly what it needs to do for not a ton of cash!

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