NEW Vacuum Tube FM Radio Vintage Audio Valve Stereo Receiver DIY/ transformers. This machine is not designed shell, enthusiasts need to use their own imagination to design their own shell. Due to the air four. Electron tube are not new production, are brand new inventory goods, please mind the friends detour. A circuit structure, working principle. This machine belongs to the typical super-aberrant radio head, high sensitivity, using electronic tubes to receive FM signals, with a strong sense of nostalgia, the sound sweet, mellow, and. The use of quadruple air capacitor tuning, is a lot of older people’s youthful feelings, the entire circuit board is made of 2mm thick PCB, increasing the mechanical strength, not easily. The entire circuit board is made of 2mm thick PCB, increasing mechanical strength and not easy to be damaged. This machine adopts a whole circuit board design design form, including high-frequency receiving, frequency conversion, IF amplification, limiting, frequency identification, stereo decoding, buffer amplification circuit, the output is a stereo amplifier. Large circuit, the output is stereo signal, can be connected to various types of tube power amplifiers, active speakers, stereo equalization amplifier and other equipment. The specific circuit configuration is as follows: high-frequency reception using dual transistor 6N3 to do high-frequency amplification and mixer amplification, dual transistor 6N1 to do the local oscillation. Mid-frequency amplification using two. The mid-frequency amplifier adopts two-stage pentode 6K4, and the limiter and frequency discriminator adopts pentode 6J4. The stereo decoding is done by LA3401, and the decoded audio signal is fed into the double triode 6N 2 for 5x amplification. After decoding, the audio signal is sent to dual triode 6N 2 for 5 times preamplification, and the stereo audio signal is output through dual RCA terminals. The quality of this machine components are carefully selected out, especially the electric. Decoder capacitors are imported black diamond or South Korea’s brand, have been tested by the voltage tester, we can rest assured that the use. Second, the use of steps. Of course, if you want to receive more radio signals, you must use an external omni-directional outdoor antenna, impedance is 75? . Please make sure that the wiring is correct, can not be wrong! From left to right wiring order is as follows. Brown – brown (11V); green – green (230-230V); blue – blue 6.3V; black – white. The two yellow (6.3V) wires are left unconnected and insulated by wrapping them in tape, so as not to short them out. The remaining two red are power cords, connected to the socket, this machine uses 220V. 3? Use RCA audio connecting cable to connect the audio output terminal of this machine with the audio input terminal of your home amplifier. 4? Turn on the power switch, the indicator light will be on, wait for about 20 seconds and then you can listen to the radio station. Rotate the tuning knob, you can select different radio signals. 5, the use of the process should be installed in the circuit board in their own design inside the shell, and the machine from the ground to have the appropriate height, remember to account for the age of children are not allowed to touch the electronic tubes and other components of the machine. Remember to explain not to allow young children to touch the machine tubes and other components, so as not to cause safety accidents! Third, the use of the process of possible problems and solutions. 1, the machine does not work, check whether the socket power? 2, the sound is small, murmur, check whether the antenna is bad? 3, there is a periodic murmur, check whether the machine around the high-frequency equipment in the work produced by the interference? Please leave note for your special request e. Please do NOT leave negative or neutral feedback without any contact. We care about our valued buyers, if you have any questions, our Customer Service staffs will be very glad to help you.