Voice extraordinary Fu-50 push-pull power amplifier production, Fu-50 Power Amplifier
Keywords: tone extraordinary Fu-50 push-pull amplifier production
Extraordinary FU-50 push-pull amplifier production
The amplifier is high as heating since the 1990s in the 1990s. It is natural and thick. Extraordinary discussed tone becomes a non-old myth in the audio family.
Playing tubes is very important. Some high prices are bile to make people look, and we are in large country, in many bile ducts, there are highly cost-effective, and FU-50 is the leader. This tube is a para-heat beam-raised five-pole, which primarily applies high-frequency oscillation or radio frequency power amplification in communication equipment, and has a small 300. The push-pull machine equipped with this tube is better than 6P3P, KT88 and other tubes, and the output power is easy to do 50W. Its high frequency is delicate, and the low frequency is steep, and it can be accommodated in conjunction with the three-point frequency phase speaker.
The motor voltage amplifies consists of a classic SRPP single-ended parallel power circuit, and the SRPP circuit has a large dynamic range, and the sound quality tends to be audio type, which is suitable in the push-pull power amplifier circuit. Since the cathode potential of the tube on this circuit is high, a positive voltage access filament end is required from the high pressure end to improve the filament potential to prevent the damage. Of course, if you use 6n11, the ECC88 is not considering this problem, and the sound will have better performance.
The push-pull surface is complicated with a low u-tube 6N6T, which is low, and the internal resistance is low, and the promotion force is better than the hot special tube 6N8P. In the push-pull amplifier produced, there are only two ways, one is a more common long-tail inverted phase, and the other is a common cathode inverted circuit. In the case where there is no dedicated instrument for amateur production, it is extremely intimate to relatively perfectly, and the co-phaneous phase circuit can be easier to get a pair of amplitudes. Positive and negative signals. This level is under the level, it is important. The post-adjustment needs to be repeatedly meticulous to make the power amplifier in low distortion, high efficiency.
Amplifier stage: The gate negative pressure of Fu-50 is fixed supply, and the negative pressure plate is installed on a 10 cm × 10cm universal board. The negative pressure adjustment potentiometer must use high-quality products, if W occurred, etc. The condition must cause an increase in the output of the power vessel to burn. This machine uses 4 ALPS precision wire wound potentiometers to ensure the safety of the machine. In this DIY, the output transformer "Kay Li" finished cattle, 350VA's fire cow is self-cultivated, and the whole machine cost is controlled.
Debug: Do not insert the tube, use the main voltage, curtain pressure, negative bias and filament voltage in the machine in the machine, and the power supply can be considered non-load state, so the voltage may be higher than the normal value. About 10% to 20% are normal. The negative bias is adjusted to the maximum value of 85V. When there is no abnormal case, turn off the power supply to insert each electronic tube, mainly adjust the inverted phase level and power output stage, and use the CD machine to play the violin "Liang Zhu", and adjust the movement of the last climax of the music. Level output music level, repeating the music fragment. When the violin solo, the frequency of the frequency band is more than 1 kHz to 4.5 kHz. It is more suitable for adjusting the inverted phase level output voltage, and the voltage between the 100V block measured the positive and negative signal and the ground is measured in the digital multimeter. When the voltage is consistent, it will be reported. When the power tube is determined to determine the screen pressure and the cathode resistance value, the power tube finely adjusts 4 gate negative pressure potentiometers W, so that the 4-act venting cathode is 0.5V, and the operating point is in the middle of the screen-flow characteristic curve. A point of position, that is, the AB1 amplification type. The machine is at least 3 times a voltage at least 3 times in a week, and it can be used normally.
Connecting audio: Source is Japan "Alpai" post six-disc CD machine + homemade 6N4T + 6N3J pre-superior + FU-50 push-pull power amplifier +8 inch two-degree "dedicated" bookshelf box, heat machine is half an hour after opening listening The extraordinary sound is completely expected.
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