Total Yin - Grid Circular Amplifier ----- Audio Preamplifier

Keywords: 共阴 - grid level amplifier Total Yin - Grid Class Amplifier It is used to obtain a low PIM distortion that the open-loop frequency of the exhibition is broadcaster. At the request of the circuit, there is a certain open loop gain, and when there is enough open-loop bandwidth, the "common yin-grid-rated colacline" (corresponding to the transistor and corresponding COSCODE circuit) is used. It is not a good choice. 1 is a driving line that the author follows the general architectural design of the "Total Yin-Grid Calm" (the other channel is the same, the power is shown "Electronic News" 2007 "2007" Direct coupling OCL electronic tube ear Put "one sheet). V1 is working in a total of. In order to improve the frequency characteristics of the common-placed large circuit, R2 introduces a sufficient amount of this grade current negative feedback. V2 works in a regular state of excellent frequency characteristics. V1, V2 is connected in series. In order to obtain a good impedance match, the cathode follower composed of V3 is inserted after V2. C5, R8, R9 introduces a parallel voltage negative feedback, the closed loop gain of the control circuit and the distortion of the entire circuit. When the open loop gain of V1 and V2 is large enough, the circuit's closed loop voltage is magnified to calculate the R8 / R9 (Ignore the effects of pre-stage output impedance) (when R8 = 200kΩ, the line can be used as a 20db pre-stage: When R8 = 680kΩ, a 30DB voltage driver can directly push the ODB no voltage gain, a combination of cholangiite. The specific line of the power level can refer to the "Electronic News" audio article. Skethed. When R8 = 680kΩ, the feedback amount of the circuit (including the insertion loss of the cathode follower), only -4db, is quite shallow (if it is too low, the open loop gain of the circuit is too low, the R2 DC resistance is still In the case of 1kΩ, the resistance can be replaced with two string resistors, and the AC bypass capacitor is connected to one of the resistors, and the negative feedback of the co-cinetical circuit is reduced, and the open loop gain of the entire circuit can be reduced. If The primary ODB-based field effect tube power amplifier selects no large loop negative feedback configuration, which is more advantageous to reduce the entire amplifier PIM, IIM and TIM distortion). V1, V2 selected in the U high-frequency voltage amplifier 6N3, operating current is 3mA, taking care of tone and input dynamics. V3 is selected 6N1, current 5mA, output impedance 220Ω (the operating state of the circuit has been set by design, no need to debug). C1, C2 Gate landing capacitance will protrude the dyeing effect of the capacitance, which should pay attention to its quality. Other elements value see circuit diagram. The amplifier (chimetry machine) driven by "common yin-grid-level circuit" except that the music is very strong enough, the most worthy of the truth is delicate, crystal clear treble, and there is no shortage of tubes. It is worth a trial. Author: 挺