Bile duct 2A3C Amplifier ----- 2A3C Power amplifer

Bile duct 2A3C Amplifier, 2A3C Power Amplifer Keywords: bile duct 2A3C A power amplifier Bile duct 2A3C A power amplifier According to the data, 2A3C is an improvement version of the original power and shore 2A3. The large glass shell of the hoist-shaped high-strength quartz glass is used, and the high-quality white porcelain holder (the pin is used by gold plating); the vacuum is more than one hundred times more than the original. Change the original dual screen structure to a single screen structure, increase the screen area and mechanical strength, and the filament and gate are also integrated, which greatly reduces the micro sound effect. The bile duct electrical performance has also increased, and the specific parameters are shown in the table. The author is shown in the power amplifier line of 2A3C. The line is a three-stage triode amplifying circuit. Its advantage is that the harmonic distortion is very small, the playback of the music is more strong, and the sense of hearing is better. The line is amplified with 1/2 6 N3, the gain is approximately 29dB, and the promotion grade is zoomed in to reduce internal resistance, the gain is about 20 dB, the line output power is 5W. 2A3C uses the fixed gate bias circuit, adjusting the resistance of W1 (or W2), and can change the operating point of 2A3C to control the static screen stream. The self-made data of the audio output transformer is as follows: the iron core width is 26mm, and the stack is 40 mm. The primary coil with a φ0.19mm oxygen-free copper wire around 3600. The secondary is wired about 224 (8Ω), or 159 (4Ω) with φ0.8mm. The primary division three sections, and the secondary division is covered in the primary medium. Iron core slipped, air gap pad 0.1mm sheet. The power of the power transformer is 200VA. The iron core width is 35mm, and the stack is 50mm. The primary use φ0.72mm wiring 512, the secondary high pressure is wired from 766. The gate pressure power supply is φ0.13mm wire around 160, 2.5V filament windings with φ.16mm wire windings, 6.3V coils with φ0.72mm line double line and around two 8th, one set of first ends and the other The tail of the group is connected as a center tap. The 5V wire coil is wound around 12 φ1.25 mm. Debug method: After the check is correct, only the flow pipe is energized, measure each filament voltage, and the screen high pressure should be substantially compliant. Tune W1 (or W2), make the gate negative pressure to -65V. Shut down, press the pressure to disappear. Power on, measure each tube screen voltage, cathode voltage substantially meets the requirements. Adjusting W1 (W2) The 2A3C cathode 10Ω resistor upper end voltage is 0.55V, and the screen stream is 55mA. The working point of the preamp and the push level can adjust the cathode resistance to match the voltage value in the line diagram. Adjusting W3 makes the speaker to communicate the smallest. After the machine is scratched 24 hours, its excellent performance is gradually displayed. With the listening, the sound is not divided with 300b, although the output power is slightly small, the price is much cheaper than 300B.