Differential single-ended daring power with 6V6, 6V6 Power Amplifier
Keywords: differential single-ended daring power with 6V6
Differential single-ended power amplifier with 6V6
Differential power amplifiers are relatively intended to have their own advantages of single-ended amplifiers and push-pull amplifiers, and avoid it, with a single-ended amplification characteristic, there is no pipeline of the push-pull machine; the common mode inhibition of push-pull machines Role, but not in the audio signal channel, and between the symmetrical two tubes, the audio harmonics are not offset, thereby saving the characteristics of single-ended championships. Typically the differential amplifier is used in the preamplis or preamplifier. If the post-level is different, the sound is added to the brocade. God! The differential amplifier made by electronic pipe, the work is stable, the signal-to-noise ratio is very high, the playback sound field is accurate, and the human music is emotional.
The electron tube difference amplifier is a two-tube cathode direct coupling amplifier. Because the two tube output signal phase is reversed, its maximum advantage is to overcome the zero drift of the amplifier, and a strong inhibitory effect on the changes of the power supply. In order to fully reflect the unique charm of the electron tube difference amplifier, the unit is tried to enlarge the two-stage differential amplification, which is that the power output stage also uses differential amplification output.
First, the principle of circuit
As far as the differential enlargement, the absolute difference will lead to the disappearance of the audio harmonic, so that the music lacks sweet, the sound is straightforward, accordingly, the load of the two-level differential enlargement is intended to be unbalanced load, while A small amount of negative feedback is applied to the pre-rated grid circuit to improve the content of high frequency harmonics. Make listening more smoothly!
The whole machine circuit is shown in the figure, the other channel is the same (omitted), and the audio signal input is directly coupled to the grid circuit by the first stage differential pipe 6N2 cathode, and then sent to the next power amplifier tube 6V6GT for differential power amplification. To drive the speaker. Since the two-stage differential enlargement is the grid circuit output, especially the power amplifier stage, greatly reduces the thermal noise and interference of the power amplifier stage, enhanced dynamic stability, so that the music is calm, self-disciplined.
Second, component selection
Electronic tubes 6N2 and 6V6GT cheap materials, easy to apply, minimize the consistency of parameters, from the perspective of production, high quality of consistency is natural, the rectifier is selected from the 5Z2P (this picture is not painted out). High Power Electric Device Selecting the electrical resistance with a porcelain pipeline and a small power resistance to select a carbon-resistant resistance. Coupled capacitors select a hint-membrane oil and a copper oil immersion capacitance that is uniform in frequency difference transmission characteristics. The native output power is above 3.5W, and the output transformer uses the core cross-sectional area of 26 mmx45mm, and the impedance is 5KΩ / 8Ω, preferably uses Z11 or H10 chip. The power transformer power can be above 150VA.
Third, installed debugging
After the whole machine is correct, the operating point can be applied to the initial adjustment of the operating point, and the power supply ethi is about 265V. By adjusting the 6V6GT cathode resistance to adjust the cathode voltage to 15V (about 45 mA per tube cathode), adjusting the 6N2 cathode resistance The voltage is adjusted to 1.5V (about 1 mA per tube cathode). After a period of initial, the machine is a period of time, then re-tests a work point, if there is offset, then adjust, adjust the relevant metader device until it meets the requirements.
Next, dynamic calibration adjustment is performed, this is a more complex process, including both the machine replacement element, including re-adjusting the tube operating point makes the tone more perfect. When the machine is connected to the system, when the two-stage yin grating is adjusted to the two-stage yin, the voltage is adjusted, and the sound is the most beautiful.
Fourth, online audition
After connecting the unit system, turn on the power supply, there is no noise in the speaker, and then open the volume potentiometer. It is still the same, indicating that the difference in differential light is excellent. Let the music, a "Taihu Beautiful" sound line is very clear, the music is clear, the sound field is not chaotic, then put a "campus morning", high school low frequency melody is magnificent, the gallbladder is rich, and the music is vigorous.
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