Fosi Audio BOX X4 User Manual Download Page 7

Troubleshooting/QA

1. Get noise/humming when turn the BOX X4 on?

• 

Please know that when no inputs connected to BOX X4, the 

  default input way is MM input mode, in this mode, the gain of 
  the amplify is much large then other input modes, so it’s 
  normal that will have some humming sound when no sound 
  pass through.

• 

Please unplug all the inputs from the BOX X4, then turn it on 

  to check if the noise still or not.

• 

If the noise disappear, the noise may from the audio source 

  or audio cable, please exchange the audio source and the 
  audio cable to try again.

• 

If the noise still, the noise may from BOX X4 or amplifier/

  speakers:

• 

Please exchange the audio cables and amplifier (powered 

  speakers) to have a try and make sure that the noise is from 
  which devices.

• 

Please volume down the “Treble” volume on the BOX X4 to 

  check if the noise volume follows or not.

• 

Please make sure all the cables completely pushed into the 

  device, incompletely 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, so it should 
  connect the 3.5mm AUX input on the BOX X4 not the 
  phono input. Also make sure the grounding wire is 
  connected well with the BOX X4, please reconnect it 
  to have a try.

 

• 

Please keep this device away from other electronic devices, 

  like the FM radio or WIFI router.

Note: 

Once 3.5mm AUX plug in, the MM input will 

            

automatically interrupted, so the input mode 

            

            

will turn

 

to 3.5mm AUX input.

            

Input priority: 3.5MM AUX input > MM turntable 

            

input. 

Step 4 :

 

Connect the power adapter to BOX X4 and the 

                socket. Turn the Multi-function Knob (Volume 
               Control/Power Switch) clockwise to power on the 
               BOX X4.

Note 1: 

The power adapter does not have a power indicator 

                light, so connecting to the socket means power is 
                on.

Note 2: 

Before connecting the power supply, please make 

                sure that the BOX X4 is in “OFF” position when                 
                connecting to the power adapter. Otherwise there is 
                a “POP” click sound from your speakers. 

Note 3: 

Before connecting the power supply, please turn 

                down the volume control, the bass and treble control 
                to 0 (always to the left) to avoid your hearing from 
                damage.
When the connection is completed, please turn on the BOX X4 
first, then turn on the amplifier (or powered speakers), at last 
turn on your turntable or other audio source, then enjoy.

Note: 

If you turn on the amplifier (or powered 

            

speakers) first, then turn on the BOX X4, there 

            

is a “POP” click sound from your speakers, it is 

            

normal that all the phono preamp have the 

            

same issues, please don’t worry about it, the 

            

“POP” click sound will not damage your 

            

amplifiers or speakers. 

Summary of Contents for BOX X4

Page 1: ...Thanks for choosing us Fosi Audio BOX X4 User Manual ...

Page 2: ...mp that converts phono signals to line level signals The BOX X4 equipping with 5654W vacuum tubes stands up to the test and will provide you with serious sound performance Input Interface MM turntable input 3 5mm AUX input 12V DC input Product Adapter Input Voltage Range AC 100V 240V DC Input Voltage 12V Applicable headphone types 16 Ω 300 Ω Output Voltage Level 1kHz and 650mV SNR 70dB THD 0 1 Fre...

Page 3: ...6 7 MM Turntable Input Grounding Post 8 9 Back Panel WWW fosiaudio com LINE IN OUTPUT MM INPUT R L R L GND DC 12V 3 5mm Headphone Output Treble Control 1 2 Bass Control Multi function Knob Volume Control Power Switch 3 4 Front Panel 1 2 3 4 BOX X4 TUBE MM PHONO PREAMP TREBLE BASS Vol ...

Page 4: ...uum Tube 2 DC 12V Power Adapter 1 User Manual 1 WWW fosiaudio com LINE IN OUTPUT MM INPUT R L R L GND DC 12V MM Turntable Input BOX X4 Preamp Tablet Laptop PC TV PS4 DVD Phone Tablet Laptop Active Speakers Passive Speakers Power Amp 3 5mm AUX Input Headphones ...

Page 5: ...e 3 5mm headphone output of BOX X4 to your headphone Step 3 INPUT Connect the audio source MM turntable input 3 5MM AUX input to the BOX X4 MM Turntable Input Use RCA Cable to connect your MM turntable to the RCA inputs of BOX X4 then connect the ground wire of your MM turntable to the grounding post of BOX X4 Note 1 If your MM turntable is no need to connect a ground wire the ground wire can be o...

Page 6: ...ion when connecting to the power adapter Otherwise there is a POP click sound from your speakers Note 3 Before connecting the power supply please turn down the volume control the bass and treble control to 0 always to the left to avoid your hearing from damage When the connection is completed please turn on the BOX X4 first then turn on the amplifier or powered speakers at last turn on your turnta...

Page 7: ...from BOX X4 or amplifier speakers Please exchange the audio cables and amplifier powered speakers to have a try and make sure that the noise is from which devices Please volume down the Treble volume on the BOX X4 to check if the noise volume follows or not Please make sure all the cables completely pushed into the device incompletely connection will cause this issue Please make sure that your tur...

Page 8: ......

Page 9: ...uum tube Please check if the music in your audio source is paused Please make sure that you are chose the correct input mode of the BOX X4 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 right but the BOX X4 does not work please try another power supply Any DC12V ...

Page 10: ...ching between the two inputs 3 5MM AUX Input MM Turntable input 5 Can I connect both headphones via 3 5mm headphone output and active speakers via RCA output to the BOX X4 at the same time Yes the BOX X4 can be connected to both outputs at the same time By the way it can be connected to both inputs at the same time When it is connected to both 3 5mm headphone output and RCA output both headphone a...

Page 11: ...You can connect the fork spade type terminal to the grounding post 9 Does this have analog to digital conversion No This product is a phono preamp tube preamplifier 10 Is the gain enough to support MC cartridge No It is for MM cartridge 11 My turntable has an optional built in phono preamp or switch to the line Can I still use this instead of my built in preamp Yes deselect the preamp on your turn...

Page 12: ...ed speakers you can directly connect this preamp to the speakers But you need to add an amplifier or receiver to the passive speakers 15 What equalization is incorporated in this preamp RIAA equalization 16 Can you hook a subwoofer to this unit Yes if your subwoofer is powered you can connect the BOX X4 directly to the subwoofer but you need add a sub amplifier between the BOX X4 and the subwoofer...

Page 13: ... 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 X4 20 Why the BOX X4 came with a broken vacuum tube Due to long distance transportation the vacuum tube may be damaged during transportation If you find that the vacuum tube is damaged or other problems please contact Fosi Audio after sales email immediately and...

Page 14: ...s have an 18 month limited warranty on parts and labor from the date of purchase Please contact us if you have any problems About Fosi Audio Fosi Audio designs and builds innovative audio products with all your music in mind Great sound simple but elegant designs high quality materials and truly useful features are what Fosi Audio is about We sincerely hope you get as much enjoyment from our produ...

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