FOSI AUDIO P1 Tube Pre-Amplifier User Manual

FOSI AUDIO P1 Tube Pre-Amplifier User Manual

Product Specifications

Fosi Audio P1 is a Mini Hi-Fi Tube Pre-Amplifier with Treble Bass Tone Control for Home Theater HiFi System, comes with two 6K4 tubes, which can be replaced by 6AK5, EF95, 5654,403B tubes. With the RCA input to the computer, CD, phone, iPod and other players, and RCA output to the Powered Speakers, active multimedia audio devices for lossless audio(The RCA cables not included). It also can be matched with a power amplifier to output passive speakers.

This pre-amp improves everything detail, transparency, immediacy, richness, tone associated with your music.

Product Overview & Control Functions

Front Panel

1. Power Switch
2. Power Light
3. Bass Control
4. Treble Control
5. Volume Control
   

Back Panel

1. RCA Input
2. RCA Output
3. DC 12V Input
   

Package Contents

• Fosi Audio P1 *1
• 6K4 Tube *2
• DC 12V Power Adapter *1
• User Manual *1

Quick Setup

1. Make sure the VOL knob is the minimum state.

2. Install the equipped 6K4 tube into the tube holder according to the direction (the tube is not divided into left and right, check whether the pin is deformed before installing the tube, the deformation can be corrected by hand).

3. (INPUT): Connect the audio source (computer, CD, phone, iPod and other player) to the P1(Use RCA Cable to connect your audio source to the RCA inputs of P1).

4. (OUTPUT): Connect active speakers to the P1. active speakers output: Use RCA cable to connect the RCA line output of P1 to your active (powered) speakers.
   Amplifier: Use RCA cable to connect the RCA line output of P1 to your amplifier, then use speaker’s wire to connect the amplifier with your passive speakers.
   Note: This is a preamplifier, not a power amplifier or phono preamp, can’t be used for turntables or passive speakers.

5. Connect the power adapter to P1 and the socket.
   Toggle the power switch on the front panel upwards to turn on this unit(The preamp power light turns red)

6. Note1: The power adapter light is on, which means that the power is turned on when connected to the socket.

7. Note2: Before opening P1, turn off the active speakers (power amplifier) first,  otherwise, there will be an impact sound, which is normal because all front stages have this problem.

8. Note3: Before connecting the power supply, please make sure that the P1 is in the “OFF” position when connecting to the power adapter. Otherwise, there is a “POP” click sound f rom your speakers.

9. Note4: Before connecting the power supply, please turn down the volume control, the bass, and treble control to 0 (always rotating counterclockwise) to avoid your hearing from damage.
   When the connection is completed, please turn on the P1 first, then turn on the active speakers (or amplifier ), at last turn on your audio source, then enjoy.

10. Note : If you turn on the active speakers (or amplifier) first, then turn on the P1, there is a “POP” click sound from your speakers, it is normal that all the preamp have the same issues. And when you want to turn off, you need to turn off the active amplifier and speakers first, and then turn off P1, otherwise there will be a “POP” click sound, please don’t worry about it, the “POP” click sound will not damage your amplifiers or speakers.

Troubleshooting/QA

Cables are connected, but no sound output?

• Check the POWER indicator is on, press the POWER button if the light is still off, At this point, you can find the same output voltage power supply (must 12V) to check if the machine or power supply failure. If the POWER indicator light is on, check whether the corresponding input signal is selected correctly.
• If the indicator light is on, check whether the VOL knob is in the minimum position. If so, turn clockwise to normal Volume.
• Check whether the two vacuum tubes are fully inserted into the jack.
• If both of the above are normal, check the input device if it is paused, mute, or the volume is minimized.

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

Why does the sound is cracking?

• This product is for the tube preamp but also can be used as a preamp, If post equipment is maxed volume & preamp too, it’s easy to distort, you just need to turn down the volume of the equipment, then ok.

Why does the volume of the machine stay the same, while the sound of different audio sources (such as CDS and mobile phones) is different?

• The output range of different types of audio source devices is different, the mobile phone is usually 0.35mV, and the CD is 1V.The signal output amplitude of the sound source will directly influence the volume.

Why do loudspeakers make a lot of electric noise?

• If you are not using the original factory standard power supply, please replace the power supply before testing. Many power supplies in the market have a large interference coefficient, which will cause a lot of current sounds.
• Because the electronic tube is vulnerable to electromagnetic interference, make sure there are no sockets, computers, radios, and other strong magnetic products around the electronic tube.
• If the above is normal, please shut down P1 and plug in and out the electronic tube again to ensure that all electronic tubes are fully connected to P1. In addition, please replace the sound source and wire and test again to confirm whether the problem is caused by the sound source or P1.

Why the speaker has a drone when I just plug in the input cable but don’t connect the sound sources?

• If you use unshielded signal lines, there will be interference signals entering the power amplifier. If you hate the sound, you are advised to use the shielded signal lines or unplug the signal lines.

Why the sound is very hard at the beginning, the 3 frequencies are not very clear, but normally after a day of use?

• The tube is a very sensitive device with good effect once the temperature should reach a degree commonly, normally about half an hour later the voice is very natural.

Can I update the tube?

• yes, we have tested and matched 6k4/6J1/6j4 / GE5654/6ak5/66*1n1n in our company. It can be replaced directly.The sound will be different with the different tubes.

Can I replace the tube without power off?

• no, it is very easy to burn the tube, because the machine works under high voltage and the hotplug will damage the tube & machine, also will hurt the people.

Can this machine connect to the phonograph/phonograph?

• At present, this model does not support the signal, input of the phonograph/gramophone because the output signal amplitude of the phonograph/gramophone is small, so it needs to increase the phonograph amplifier. If you would like to connect the phonograph, you can choose our phono preamplifiers, such as BOX X1, BOX X2, BOX X4.

Can I hook the P1 to the power amplifier for my system?

• Yes. You can connect the P1 to the power amplifier through the RCA output.

Can I directly connect this preamp to the speakers?

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

Sound quality is not good?

• Make sure all the cables are fully connected.
• Adjust the treble and bass control of the P1 to achieve the right tone.
• Check if the vacuum tube is broken or not plugged in properly.
• Please try to change the sound source and cables to test.

Can I plug my turntable in to this and out put to preamplifier?

• Please know that this is not phono preamp, you can connect this to your phono preamplifier, if your turntable doesn’t need the phono preamp, you can connect it directly to turntable.

Will there be signal loss if i put rca splitters on the output to send 1 to a recorder and the other to an amplifier, basically making 4 rca outputs?

• You can use a one-in-two RCA line to put RCA splitters, no signal loss.

Why does p1 have sound in only one channel?

• I Left and right swap the electronic tube test.
• Adjust the left and right input wire test.
• Switch the left and right output lines to test.
• If the above or only one channel has sound, please replace the audio source, wire and speaker (amplifier) and then test to confirm whether the problem is in P1.

Why the P1 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 we will replace the vacuum tube for you.

Any problems please leave a message to the customer support email address: support@fosiaudio.com.

Warranty Information

• All Fosi Audio products 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 products as we’ve had to create them!

Our website: www.fosiaudio.com
Amazon store: www.amazon.com/fosiaudio

Our Youtube channel: Fosi Audio
Our Facebook page: Fosi Audio

After-sale Service and Technical Support Email:
support@fosiaudio.com
fosiaudio@hotmail.com

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