Two flavor unique fare-level, Vacuum Tube Preamplifier
Keywords: two flavor unique fare-level
Two flavor unique fare-level
The enthusiasts have a pure level of my favorite, or a timid, or stone machine, or a soil gun, or a foreign gun. Different amplifiers have their own intrinsic features. From the state of the country, most of my country's enthusiasts in China is a working class, and there are very few people who really enjoy the wonderful tone of the platter. This article introduces the readers to two distinctive dilerous premiums, and use it to dispense all kinds of post-level amplifiers, and you can get a charming tone of ambiguous. In particular, it is more likely to be "listened" with the pureroa-level amplifier that is launched by the company. DS-9908 fare-level
The principle is shown in Figure 1. At first glance, it seems to have met. It is quite similar to the Marantz-7 timid stage, which is exactly the same. First let us simply analyze the principle of circuit, it is not difficult to find. The audio signal is input from the V1 gate, output from the screen, is amplified and reverse phase; and then the C2 coupled to the V2 gate, and the V2 is further enlarged and reversed again, and outputs one from the V2 screen to the amplifier input signal in phase. Audio signal; currently enlarged by R9 buffer V3, and reduces impedance by C3 coupling from Wi output. V3 and V2 are connected to a direct coupling cathode follower, and the gate bias of V3 acquires from the V2 screen, eliminating the pole coupling capacitance necessary to self-biased cathode follower, which is advantageous for the smooth passage of the low frequency signal. Thereby showing the frequency band and opens the sound field. The feedback signal is taken out of the V2 screen, and V1 cathode is fed by C10, R5. C10, R5 is fed in V1 cathode. C10, R5, R2, C1 together constitute a negative feedback network. Change the value of R5, R2, and C1 to obtain different hearing effects (readers can achieve their satisfactory results by changing the values of R5, R2, C1). Different than Marantz-7, the difference between V2, V3 is coupling and feedback. The MARANTZ-7 V3 uses a self-propelled mode of mode of mode, and the connection between V2 is used in series from the serial reference point from the serial contact. This is not a general coupling, and is clearly a high-pass filter. Through practice, if it is made according to some of the Marantz-7 circuits published on some article magazines, it is not necessary to achieve the expected effect, and its playback effect is not satisfactory. However, DS 1 9908 daring stage is otherwise, this pre-level is changed from the M7 circuit, with DS - 9908 direct stamp amplifier. Played music, each frequency band is flat, low frequencies are magnificent, moving, surprising, bright, sweet, very magnetic, treble, fungus, slightest. Its playback effect is a flavor. DS-9908 SRPP timid stage
The schematic diagram of the SRPP timid stage is shown in Figure 2. This is an improved SRPP circuit that has been introduced in many audio publications. It seems that there is nothing special. This pre-stage adopts the AC voltage negative feedback technique that is not employed in general SRPP circuits, so that the signals of the circuit to each frequency band tend to flat, and can effectively improve distortion. After introducing negative feedback, the low frequency of the lack of effort is enhanced, and the sound field also extends. The working principle is briefly described as follows: SRPP circuit, from an enlarged process of AC signal, is actually a parallel push-pull amplifier that people often say. However, from the principle of DC operation, it is connected in series in the power supply loop. Each triode gate is used in a self-sufficient bias mode, and V2 is riding on the V1, so this circuit has been enthusiastically draped as "horse riding circuit". The signal is fed from R1, C1 to the V1 gate, and the VL is enlarged by a signal opposite to the input signal, and then the C4 coupled to the V2 gate, the current amplification and impedance transformation, from the V2 yin C5 , W1 output. The negative feedback signal is taken out of the V1 screen, and a negative feedback network is constituted by C10. Change the value of C10, stickers, C1, R1, and obtain different tones. Use this pre-staple straight-cast power amplifier, the music played is very emotional, low frequent, uncomfortable and elastic, the intercourse is clear, the people are full, the tread is clear and clear, and the positioning is accurate.
These two kinds of timids can directly drive 32Ω stereo headphones, and W1 must be moved to the input when the headset is driven. They use the same set of power, as shown in FIG. 3, the principle reader is analyzed by the reader (this precursor is different when the voltage difference is different, and the playback effect is good when the power screen is about DC450V). . The bile duct filaments are powered by 6.3V. Use 3212 headphones to listen to the maximum, the communication sound can be ignored; dismount the power amplifier, open the large volume, the ear is 20EM, and there is no exchange. Signal noise Bigda 90db or more. When making, the resistance except for the power person, preferably L / 2W or more gold film resistance; electrolytic capacitance should be selected to choose ruby, withstand voltage, capacity (non-polar capacitor preferred RIFA or WiMA MKP; gallbladder selection J-class or more.
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