1: Getting a buzz when turning the BOX X2 on?

• Please know that when no inputs are connected to BOX X2, the default input way is MM input mode, in this mode, the gain of the amplify is much more significant than in other input modes, so it’s expected that it will have some humming sound when no sound pass through.
• Please unplug all the inputs from the BOX X2, then turn it on to check if the noise is still there or not.
• If the noise disappears, it may be from the audio source or audio cable; please exchange the audio source and the audio cable to try again.
• If the noise is still, the noise may be from BOX X2 or amplifier/ speakers:
• Please exchange the audio cables and amplifier (powered speakers) to try and make sure that the noise is from which devices.
• Please check whether the gain is too high; the bottom noise may be more prominent if the gain is too high.
• Please make sure all the cables are completely pushed into the device; an incomplete connection will cause this issue.
• Please make sure that your turntable is MM output and Also, make sure that it is phono output; some turntables’ built-in phono preamplifier should connect to the 3.5mm AUX input on the BOX X2, not the phono input. Also, make sure the grounding wire is connected well with the BOX X2; please reconnect it to have a try.
• Please keep this device away from other electronic devices, like the FM radio or WiFi router.
• Please ensure the tubes are completely pushed into the socket; an incomplete connection will cause this issue.
• Please reconnect the power adapter to the BOX X2 to try again.

Note: • If the noise persists, please contact us via email at support@fosiaudio.com. BOX X2 is a preamplifier, not a power amplifier, and can not be connected with passive speakers directly.

2. All cables are connected, but there is no audio output?

• Please check if your audio source, BOX X2, amplifier, or powered speakers are all turned on and working mode.
• Please check whether the light of the vacuum tube is always on after power on, and check whether there is a problem with the vacuum tube.
• Please check if the music in your audio source is paused.
• Please make sure that you choose the correct input mode of the BOX X2; if the 3.5mm AUX input plug in, the MM input mode will be interrupted; at this time, if you want to use the MM input, you need to disconnect the 3.5mm AUX input first.
• If the connection is proper, but the BOX X2 does not work, please try another power supply (Any DC12V power adapter can work with the BOX X2, you can use the power adapter of the WIFI router or camera) that is suitable for the BOX X2. If BOX X2 works after replacing the appropriate power adapter, it means that the power adapter is probably broken; please contact us to replace the power adapter; if BOX X2 still does not work after replacing the appropriate power adapter, it means that the BOX X2 is probably broken, don’t hesitate to get in touch with us to replace the BOX X2.

Note: Make sure that all the cables are completely pushed into the device.

3. How to distinguish between Power Switch and Gain Adjustment Switch?

• Power switch means turning the power switch knob(multi-function knob) clockwise for one time to power on the BOX X2. Adjusting the gain means turning the gain adjustment knob (multi-function knob) clockwise to adjust the gain.

4. How do you switch between inputs?

• The BOX X2 supports two inputs: MM turntable input and 3.5mm AUX Input.

The priority of switching between the two inputs: 3.5MM AUX Input> MM Turntable input.

5. My turntable doesn’t have a ground wire connection. Does this need a ground wire hooked up for it to be able to work?

• No, it does not need a ground wire to operate. However, if your turntable has any ground loop, it will be piped and amplified through the BOX X2.

6. How to attach ground wire?

• Here is a post to attach the ground wire.

7. How does grounding post work? Does my turntable have a fork spade-type terminal?

• You can connect the fork spade type terminal to the grounding post.

8. Does this have an analog to digital conversion?

• No. This product is a phono preamp/tube preamplifier.

9. Is the gain enough to support the MC cartridge?

• No. It is for the MM cartridge.

10. My turntable has an optional built-in phono preamp or switches to the line. Can I still use this instead of my built-in preamp?

• Yes, deselect the preamp on your turntable.

Note: Please confirm whether your turntable has a built-in phono preamp; if there is a phono preamp, and it cannot be deselected, then you can only connect 3.5 mm input and can not connect MM Turntable input.

11. Can I hook the BOX X2 to the power amplifier for my system?

• Yes. You can connect the BOX X2 to the power amplifier through the RCA output.

12. Can this work with my turntable and headphones？

• This can not work with headphones because it does not have headphones output.

13. Can I directly connect this phono preamp to the speakers?

• You can directly connect this preamp to the speakers if your speakers are powered speakers. But you need to add an amplifier or receiver to the passive speakers.

14. What equalization is incorporated in this preamp?

• RIAA equalization.

15. Can you hook a subwoofer to this unit?

• Yes, if your subwoofer is powered, you can connect the BOX X2 directly to the subwoofer, but you need to add a sub amplifier between the BOX X2 and the subwoofer if your subwoofer is passive.

16. Which vacuum tube can be replaced by the BOX X2?

• If necessary, the tubes below are substitutions: GE 5654 EF95, 6AK5, 6AK5W, 403A/403B, 6J1, 6J1P, 6J2, 6J3, 6J4, 6J5 vacuum tubes, etc. You can replace the vacuum tubes to DIY your stereo system.

17. Is the Sound quality not good?

• Make sure all the cables are fully connected.
• Adjust the gain of the BOX X2 to achieve the right tone.
• Please try to change the sound source and cables to test.

18. Can it be left on all the time?

• The BOX X2 is designed with a power switch. It can stay connected safely without power consumption all the time; you only need to turn off the power switch on the BOX X2.

19. Why does the BOX X2 come with a broken vacuum tube?

• Due to long-distance transportation, the vacuum tube may be damaged during transport. If you find that the vacuum tube is damaged or has other problems, please contact Fosi Audio.

After-sales email immediately, and we will replace the vacuum tube for you.

If you have any problems, please leave a message to the customer support email address: support@fosiaudio.com.