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CN-224233658-U - External electron tube power amplifier with tone color selection function

CN224233658UCN 224233658 UCN224233658 UCN 224233658UCN-224233658-U

Abstract

The utility model provides an external electronic tube power amplifier with tone selection function, which is connected with an external tone selection circuit, wherein a voltage amplification stage circuit is used for providing voltage gain and outputting a first driving signal to a voltage pushing stage circuit, a grid electrode of a third triode amplifier of the voltage pushing stage circuit is input with the first driving signal, a midpoint of a filament resistor of the voltage pushing stage circuit is connected with a first bias circuit, an anode of the voltage pushing stage circuit is used for outputting a second driving signal to the power amplification stage circuit, the power amplification stage circuit is used for carrying out power amplification on the second driving signal, an output end of a transformer output circuit is connected with a loudspeaker and is used for outputting the third driving signal to drive the loudspeaker after impedance matching, and the tone selection circuit is a multi-stage large-loop negative feedback circuit for reducing the total gain of the electronic tube power amplifier circuit. The utility model changes the feedback quantity through the design of the multistage large-loop negative feedback circuit so as to control the circuit gain, thereby achieving the effects of realizing the output of different audio signals and having good circuit stability.

Inventors

  • CHEN DEHAI

Assignees

  • 珠海斯巴克电子设备有限公司

Dates

Publication Date
20260512
Application Date
20250508

Claims (10)

  1. 1. An external valve power amplifier with tone color selection function, which is characterized by being connected with an external tone color selection circuit, comprising: The input end of the power amplification stage circuit is connected with the input end of the transformer output circuit and is used for carrying out power amplification on the second driving signal, the output end of the transformer output circuit is connected with a loudspeaker and is used for outputting a third driving signal to drive the loudspeaker after impedance matching, and the input and output ends of the tone selection circuit are respectively connected with the output end of the transformer output circuit and the input end of the voltage amplification stage circuit to form a multi-stage large loop negative feedback circuit for reducing the total gain of the electronic tube power amplifier; The tone color selection circuit at least comprises a resistor topology and a tone color switch, wherein the resistor topology is used for carrying out signal adjustment on an input negative feedback signal and then outputting the signal to the input end of the voltage amplification stage circuit, and the tone color switch is connected with the resistor topology and used for adjusting the feedback quantity output by the resistor topology through gear switching.
  2. 2. The external valve power amplifier with tone color selection function according to claim 1, wherein: The voltage amplification stage circuit is a two-stage voltage amplification circuit and comprises a first voltage amplification stage circuit and a second voltage amplification stage circuit, wherein the input end of the first voltage amplification stage circuit is used for inputting the voltage signal, providing voltage gain and outputting a first inversion signal opposite to the phase of the voltage signal to the second voltage amplification stage circuit, and the second voltage amplification stage circuit is used for providing secondary voltage gain and outputting a first driving signal identical to the phase of the voltage signal.
  3. 3. The external valve power amplifier with tone color selection function according to claim 2, wherein: The first voltage amplification stage circuit and the second voltage amplification stage circuit are both common-cathode type phase inverter circuits, the first voltage amplification stage circuit comprises a first triode amplifier, a first RC coupling amplification circuit and a first resistor, the grid electrode of the first triode amplifier is connected with the voltage signal, the anode of the first triode amplifier is connected with the first RC coupling amplification circuit, the first phase inverter signal is coupled to the second voltage amplification stage circuit through the first RC coupling amplification circuit, and the cathode of the first triode amplifier is grounded through the first resistor; the second voltage amplification stage circuit comprises a second triode amplifier, a second RC coupling amplification circuit and a third RC coupling amplification circuit, wherein the grid electrode of the second triode amplifier is connected with the first inversion signal, the anode of the second triode amplifier is connected with the second RC coupling amplification circuit, the first driving signal is coupled to the voltage pushing stage circuit through the second RC coupling amplification circuit, and the cathode of the second triode amplifier is grounded through the third RC coupling amplification circuit.
  4. 4. A valve power amplifier with external tone color selection function according to claim 3, wherein: The first triode amplifier and the second triode amplifier are respectively 6SN7GTB side-heating type middle mu double triodes.
  5. 5. The external valve power amplifier with tone color selection function according to claim 1, wherein: The third triode amplifier adopts a 300B direct heating triode.
  6. 6. The external valve power amplifier with tone color selection function according to claim 5, wherein: The first bias circuit is used for providing self-bias voltage for the third triode amplifier and comprises a first capacitor, a second resistor and a third resistor, wherein the first capacitor is an electrolytic capacitor, the positive electrode of the first capacitor is connected with the midpoint of the filament resistor of the third triode amplifier, the negative electrode of the first capacitor is connected to the grid electrode of the third triode amplifier in a feedback way through the second resistor and the third resistor which are connected in series, one end of the second capacitor is used as a bypass capacitor, the other end of the second capacitor is connected with the midpoint of the filament resistor of the third triode amplifier, and the other end of the second capacitor is connected to the common connecting end of the second resistor and the third resistor.
  7. 7. The external valve power amplifier with tone color selection function according to claim 1, wherein: The power amplifier stage circuit comprises a fourth triode amplifier and a fourth resistor, wherein the fourth triode amplifier is a 845SL directly-heated triode, a grid electrode of the fourth triode amplifier inputs the second driving signal, the midpoint of a filament resistor of the fourth triode amplifier is grounded through the fourth resistor, and an anode of the fourth triode amplifier is connected with the input end of the transformer output circuit.
  8. 8. The external valve power amplifier with tone color selection function according to claim 1, wherein: The transformer output circuit is provided with four output ends with output impedance of 8Ω, 6Ω, 4Ω and 0Ω, and is used for driving speakers with different rated impedance values through impedance matching.
  9. 9. A valve power amplifier with external tone color selection function according to claim 3, wherein: The resistor topology is a resistor series topology structure and comprises a fifth resistor and a sixth resistor, wherein the fifth resistor and the sixth resistor are connected in series to form a first resistor series circuit, one end of the fifth resistor is connected with the output end of the transformer output circuit, and the other end of the fifth resistor is connected to the cathode of the first triode amplifier through the sixth resistor; The tone switch is connected with two ends of the sixth resistor in parallel, and the fifth resistor or the first resistor series circuit is switched and connected into the multistage large-loop negative feedback circuit through the action of the tone switch, so that the circuit gain is adjusted to realize the selection of two tone circuits.
  10. 10. The external valve power amplifier with tone color selection function according to any one of claims 1-9, wherein: The tone color selection circuit comprises a plurality of resistor topologies and tone color switches, the tone color switches are multisection contact transfer switches, a plurality of groups of contacts of the tone color switches are respectively connected with the resistor topologies, and feedback quantity input by the voltage amplification stage circuit is adjusted by rotating gears of the tone color switches, so that the total gain of the circuit is controlled to realize multi-tone color switching of the valve power amplifier.

Description

External electron tube power amplifier with tone color selection function Technical Field The utility model relates to the field of audio playing equipment, in particular to an external electronic tube power amplifier with a tone selection function. Background In the field of audio playing, the valve power amplifier can generate rich harmonic waves due to the nonlinear characteristics of the valve power amplifier, so that sound is more stereo, and the valve power amplifier is widely applied to a power amplifier circuit of audio playing equipment. The existing electron tube power amplifier mainly comprises an electron tube, a transformer, an output transistor and the like, and the working principle of the existing electron tube power amplifier is that an audio signal is amplified through an electron tube power amplifier circuit, so that sound is clearer and more full. The electronic tube is used as a signal amplifier, the gain of the signal is controlled to realize the fine adjustment of the audio signal, the transformer is responsible for converting alternating current into direct current to provide energy for the electronic tube, and the output transistor is responsible for amplifying and outputting the signal of the electronic tube. However, the electronic tube power amplifier circuit of the existing music player provides a single tone color, and even a higher-end music player is still pursuing high fidelity tone quality, so that the requirement of listeners on tone color diversity is often ignored. In addition, it is a problem to redesign the power amplifier circuit of the electronic tube of the music player to provide various tone color selection functions, and how to design the power amplifier based on the electronic tube to have good stability and improve the quality of the output signal. Therefore, in order to further enrich the tone selection of the audio playback apparatus, there is a need for a valve power amplifier that can realize different tone selection functions and that has good circuit stability. Disclosure of utility model The utility model provides an external electronic tube power amplifier with tone color selection function, which is mainly used for solving the problems of single tone color, circuit stability design of a power amplifier with multiple tone color selections and the like of the traditional music player, thereby achieving the effects of realizing different tone color selection functions and having good circuit stability. The utility model realizes the above purpose through the following technical scheme: The electronic tube power amplifier with the external tone color selection function is connected with an external tone color selection circuit and comprises a voltage amplification stage circuit, a voltage pushing stage circuit, a power amplification stage circuit and a transformer output circuit, wherein the input end of the voltage amplification stage circuit is used for inputting voltage signals and providing voltage gain and outputting first driving signals to the voltage pushing stage circuit, the voltage pushing stage circuit comprises a third triode amplifier and a first bias circuit, the grid electrode of the third triode amplifier is used for inputting the first driving signals, the midpoint of a filament resistor of the third triode amplifier is connected with the first bias circuit, the anode of the third triode amplifier is used for outputting second driving signals to the power amplification stage circuit, the output end of the power amplification stage circuit is connected with the input end of the transformer output circuit and used for amplifying the power of the second driving signals, the output end of the transformer output circuit is connected with a loudspeaker and outputting third driving signals to drive the loudspeaker after impedance matching, and the input end of the tone color selection circuit is respectively connected with the output end of the transformer output circuit and the voltage amplification stage, and the input end of the voltage amplification stage is used for forming a multi-stage loop amplifier total gain circuit. The tone color selection circuit at least comprises a resistor topology and a tone color switch, wherein the resistor topology is used for carrying out signal adjustment on an input negative feedback signal and then outputting the signal to the input end of the voltage amplification stage circuit, and the tone color switch is connected with the resistor topology and used for adjusting the feedback quantity output by the resistor topology through gear switching. The voltage amplifying stage circuit is a two-stage voltage amplifying circuit and comprises a first voltage amplifying stage circuit and a second voltage amplifying stage circuit, wherein the input end of the first voltage amplifying stage circuit is used for inputting the voltage signal and providing voltage gain, and outputting a first inversion signal with the p