Impedance adjusting audio adapter

Abstract

The utility model relates to an impedance adjusting audio adapter, which is used between an earphone and a playing device and comprises a shell, an audio output plug and an audio input socket. One of the audio output plug and the audio input socket is used for connecting an earphone, and the other one is used for connecting playing equipment; the shell is provided with a multi-gear impedance manual adjusting circuit used for manually adjusting audio impedance. The audio output plug is connected with the audio input socket through the multi-gear impedance manual adjusting circuit. Corresponding impedance adjustment can be manually carried out according to use requirements, the flexibility is good, the earphone is prevented from being excessively pushed, and the service life of the earphone is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of impedance-adjustable audio adapter technology, and in particular to an impedance-adjustable audio adapter. Background Technology

[0002] Headphone sensitivity refers to the sound pressure level (SPL) that headphones can produce when inputting 1 milliwatt of power (the unit of SPL is decibels; the higher the SPL, the louder the volume). Generally, higher sensitivity and lower impedance make headphones easier to produce sound and easier to drive.

[0003] However, if the headphones are too sensitive and the playback device has too much output power, the headphones will be "overdriven." Over-driving means that the power received by the headphones exceeds their design capacity.

[0004] Overpushing can lead to the following problems:

[0005] 1. Sound quality distortion: Over-driving the headphones will cause sound quality distortion, making the sound unclear, or even causing distortion.

[0006] 2. Headphone damage: Over-driving for extended periods may damage the headphone's driver unit and shorten its lifespan.

[0007] Later, to avoid over-driving headphones, a fixed-impedance adapter was typically used. For example, if a headphone with excessively high sensitivity was used, it would be connected to a fixed-impedance adapter before being connected to a playback device with excessive output power. However, this approach has drawbacks. It requires purchasing and replacing adapters with different impedances to adapt to different headphones and playback devices, significantly increasing usage costs and reducing flexibility.

[0008] Therefore, in this utility model patent application, the applicant has carefully researched an impedance-adjustable audio adapter to solve the above problems. Utility Model Content

[0009] The present invention addresses the shortcomings of the prior art by providing an impedance-adjustable audio adapter that allows manual adjustment of impedance according to usage requirements, offering greater flexibility and preventing over-driving of headphones, thus extending their lifespan.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] An impedance-adjustable audio adapter for use between headphones and a playback device includes a housing, an audio output plug, and an audio input jack.

[0012] Of the audio output plug and audio input jack, one is used to connect headphones and the other is used to connect a playback device.

[0013] The housing is equipped with a multi-position manual impedance adjustment circuit for manually adjusting the audio impedance.

[0014] The audio output plug is connected to the audio input socket via a multi-position impedance manual adjustment circuit.

[0015] As a preferred embodiment, the multi-position impedance manual adjustment circuit includes a multi-position toggle switch and an impedance matching circuit connected together, and the audio output plug is connected to the audio input socket through the multi-position toggle switch and the impedance matching circuit.

[0016] As a preferred embodiment, the impedance matching circuit includes a first resistor, a second resistor, a third resistor, and a fourth resistor;

[0017] The multi-position toggle switch has a toggle key and contacts 1 to 14. Contacts 1 and 2 are connected to the positive terminal of the left channel of the audio output plug, contact 3 is connected to the positive terminal of the left channel of the audio input jack, contacts 8 and 9 are connected to the positive terminal of the right channel of the audio output plug, and contact 310 is connected to the positive terminal of the right channel of the audio input jack.

[0018] Each of the first to fourth resistors has two resistors. Contact 4 is connected to the positive left channel of the audio input jack through one of the first resistors. Contact 5 is connected to the positive left channel of the audio output plug through one of the second resistors. Contact 6 is connected to the positive left channel of the audio output plug through one of the third resistors. Contact 7 is connected to the positive left channel of the audio input jack through one of the fourth resistors.

[0019] Contact 11 is connected to the positive left channel of the audio input jack through another first resistor; contact 12 is connected to the positive left channel of the audio output plug through another second resistor; contact 13 is connected to the positive left channel of the audio output plug through another third resistor; and contact 14 is connected to the positive left channel of the audio input jack through another fourth resistor.

[0020] The toggle key has a first end, a second end, a third end, and a fourth end. The first end and the second end are connected, and the third end and the fourth end are connected. The first end can be selectively connected to contact points 1 to 5, the second end can be selectively connected to contact points 3 to 7, the third end can be selectively connected to contact points 8 to 12, and the fourth end can be selectively connected to contact points 10 to 14.

[0021] As a preferred embodiment, the resistance values ​​of the first resistor, the second resistor, the third resistor, and the fourth resistor are not the same; the resistance values ​​of the two first resistors are the same; the resistance values ​​of the two second resistors are the same; the resistance values ​​of the two third resistors are the same; and the resistance values ​​of the two fourth resistors are the same.

[0022] As a preferred embodiment, the impedance matching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor;

[0023] The multi-position toggle switch has a double-pole switch and contacts 1 to 14. One end of each of the two knife switches of the double-pole switch is connected to contact 8 and contact 1 respectively. By toggling the double-pole switch, the other end of each of the two knife switches can be selectively connected to contact 14 and contact 7, or to contact 13 and contact 6, or to contact 12 and contact 5, or to contact 11 and contact 4, or to contact 10 and contact 3, or to contact 9 and contact 2. Contact 8 and contact 1 are respectively connected to the positive terminals of the left and right channels of the audio output plug.

[0024] Each of the first to fifth resistors has two resistors. Contact 14 is connected to the positive terminal of the left channel of the audio input jack. Contact 13 is connected to the positive terminal of the left channel of the audio input jack through one of the first resistors. Contact 12 is connected to the positive terminal of the left channel of the audio input jack through one of the second resistors. Contact 11 is connected to the positive terminal of the left channel of the audio input jack through one of the third resistors. Contact 10 is connected to the positive terminal of the left channel of the audio input jack through one of the fourth resistors. Contact 9 is connected to the positive terminal of the left channel of the audio input jack through one of the fifth resistors.

[0025] Contact 7 is connected to the positive terminal of the right channel of the audio input jack. Contact 6 is connected to the positive terminal of the right channel of the audio input jack through another first resistor. Contact 5 is connected to the positive terminal of the right channel of the audio input jack through another second resistor. Contact 4 is connected to the positive terminal of the right channel of the audio input jack through another third resistor. Contact 3 is connected to the positive terminal of the right channel of the audio input jack through another fourth resistor. Contact 2 is connected to the positive terminal of the right channel of the audio input jack through another fifth resistor.

[0026] As a preferred embodiment, the audio output plug is located at the front of the housing, and the audio input socket is located inside the housing with the insertion port of the audio input socket exposed on the rear side of the housing.

[0027] As a preferred embodiment, the multi-position toggle switch also has a toggle block for moving the toggle key when toggled;

[0028] A circuit board is provided inside the housing, the multi-position impedance manual adjustment circuit is provided on the circuit board, and the toggle block of the multi-position toggle switch extends out of the upper end surface of the housing.

[0029] The audio output plug is connected to the multi-position impedance manual adjustment circuit of the circuit board via a wire extending into the housing. The audio input socket is located on the circuit board and is connected to the multi-position impedance manual adjustment circuit of the circuit board.

[0030] As a preferred embodiment, the upper end face of the housing is provided with an adjustment groove for the displacement of the actuating block, and the actuating block is slidably mounted in the adjustment groove.

[0031] As a preferred embodiment, the adjustment slot extends in the front-to-back direction, and the multi-position toggle switch is located on the left or right side of the audio input jack.

[0032] As a preferred embodiment, the adjustment slot extends in the left-right direction, and the multi-position toggle switch is located in front of the audio input jack.

[0033] Compared with the prior art, this utility model has obvious advantages and beneficial effects. Specifically, it mainly sets a multi-level impedance manual adjustment circuit between the audio output plug and the audio input socket, which can manually adjust the corresponding impedance according to the usage requirements, which is more flexible and avoids over-driving the headphones, thus extending their service life.

[0034] Secondly, through the specific circuit structure of the multi-level impedance manual adjustment circuit, the five-level impedance adjustment is maximized, which can then be adapted to a variety of playback devices with different output power, making it highly versatile.

[0035] Furthermore, the adjustable groove's left-right and front-back structural design can accommodate different user habits. Attached Figure Description

[0036] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0037] Figure 2 This is a partial structural schematic diagram of an embodiment of the present utility model (mainly showing the circuit board audio input socket box and multi-position toggle switch);

[0038] Figure 3 This is a schematic diagram of another embodiment of the present utility model;

[0039] Figure 4 This is a partial structural schematic diagram of another embodiment of the present invention (mainly showing the circuit board audio input socket box and multi-position toggle switch);

[0040] Figure 5 This is a schematic diagram of the first gear state circuit according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the second gear state circuit according to an embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of the third gear state circuit according to an embodiment of the present invention;

[0043] Figure 8This is a schematic diagram of the fourth gear state circuit according to an embodiment of the present invention;

[0044] Figure 9 This is a schematic diagram of the fifth gear state circuit according to an embodiment of the present invention;

[0045] Figure 10 This is a circuit diagram of a multi-position impedance manual adjustment circuit according to another embodiment of the present invention (showing the fifth position).

[0046] Explanation of icon numbers:

[0047] 10. Audio output plug 11. Cable

[0048] 20. Shell

[0049] 21. Circuit board 22. Adjustment slot

[0050] 30. Audio input jack

[0051] 40. Multi-stage impedance manual adjustment circuit

[0052] 41. Multi-position toggle switch

[0053] 411. Toggle key 412. Toggle block

[0054] 42. Impedance matching circuit. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0056] like Figures 1 to 10 As shown, an impedance-adjustable audio adapter for use between headphones and a playback device includes a housing 20, an audio output plug 10, and an audio input jack 30.

[0057] Of the audio output plug 10 and the audio input socket 30, one is used to connect headphones and the other is used to connect a playback device.

[0058] The housing 20 is equipped with a multi-position impedance manual adjustment circuit 40 for manually adjusting the audio impedance. A circuit board 21 is housed inside the housing 20, and the multi-position impedance manual adjustment circuit 40 is mounted on the circuit board 21. The audio output plug 10 is connected to the audio input jack 30 via the multi-position impedance manual adjustment circuit 40.

[0059] The multi-position impedance manual adjustment circuit 40 includes a multi-position toggle switch 41 and an impedance matching circuit 42 connected together. The audio output plug 10 is connected to the audio input socket 30 through the multi-position toggle switch 41 and the impedance matching circuit 42.

[0060] In this embodiment, the impedance matching circuit 42 includes a multi-position toggle switch 41, a first resistor, a second resistor, a third resistor, and a fourth resistor; two of each of the first to fourth resistors are provided.

[0061] The resistance values ​​of the first, second, third, and fourth resistors are not the same; the resistance values ​​of the two first resistors are the same; the resistance values ​​of the two second resistors are the same; the resistance values ​​of the two third resistors are the same; and the resistance values ​​of the two fourth resistors are the same. The resistance values ​​of the first, second, third, and fourth resistors increase sequentially. The resistance value of the second resistor is twice the resistance value of the first resistor. Preferably, the two first resistors (e.g., Figures 5 to 9 The resistance values ​​of resistors R1 and R6 are both 16.2 ohms, and the two second resistors (such as...) Figures 5 to 9 The resistance values ​​of resistors R2 and R7 are both 32.4 ohms, and the two third resistors (such as...) Figures 5 to 9 The resistance values ​​of resistors R3 and R8 are both 61.9 ohms, and the two fourth resistors (such as...) Figures 5 to 9 The resistance values ​​of resistors R4 and R9 are both 150 ohms.

[0062] The multi-position toggle switch 41 has a toggle key 411, contacts 1 to 14, and a toggle block 412 for moving the toggle key 411 when toggled.

[0063] The multi-position toggle switch 41 also has a toggle block 412 for moving the toggle key 411 when toggled. The toggle block 412 of the multi-position toggle switch 41 extends out of the upper end face of the housing 20; the upper end face of the housing 20 is provided with an adjustment groove 22 for displacing the toggle block 412, and the toggle block 412 is slidably mounted in the adjustment groove 22.

[0064] The adjustment slot 22 extends in the front-to-back direction, and the multi-position toggle switch 41 is located on the left or right side of the audio input jack 30. In this embodiment, the multi-position toggle switch 41 is located on the right side of the audio input jack 30. In another embodiment, the adjustment slot 22a extends in the left-to-right direction, and the multi-position toggle switch 41 is located in front of the audio input jack 30.

[0065] The seven contacts 1 to 7 are symmetrically arranged with the seven contacts 8 to 14, that is, contacts 1 and 8 are symmetrically arranged, contacts 2 and 9 are symmetrically arranged, contacts 3 and 10 are symmetrically arranged, contacts 4 and 11 are symmetrically arranged, contacts 5 and 12 are symmetrically arranged, contacts 6 and 13 are symmetrically arranged, and contacts 7 and 14 are symmetrically arranged.

[0066] Contacts 1 and 2 are connected together to the positive terminal of the left channel of the audio output plug 10 (e.g., ...). Figures 5 to 9 (L+), contact 3 is connected to the positive terminal of the left channel of the audio input jack 30 (e.g., L+). Figures 5 to 9 (4.4mm L+), contacts 8 and 9 are connected together to the right channel positive terminal of the audio output plug 10 (e.g., 4.4mm L+). Figures 5 to 9 (R+), contact 310 connects to the right channel positive terminal of audio input jack 30 (e.g., R+), Figures 5 to 9 (4.4mm R+);

[0067] Contact 4 is connected to the positive left channel of the audio input jack 30 through one of the first resistors; contact 5 is connected to the positive left channel of the audio output plug 10 through one of the second resistors; contact 6 is connected to the positive left channel of the audio output plug 10 through one of the third resistors; and contact 7 is connected to the positive left channel of the audio input jack 30 through one of the fourth resistors.

[0068] Contact 11 is connected to the positive left channel of the audio input jack 30 through another first resistor, contact 12 is connected to the positive left channel of the audio output plug 10 through another second resistor, contact 13 is connected to the positive left channel of the audio output plug 10 through another third resistor, and contact 14 is connected to the positive left channel of the audio input jack 30 through another fourth resistor.

[0069] The toggle key 411 has a first end, a second end, a third end, and a fourth end. The first end and the second end are connected, and the third end and the fourth end are connected. The first end can selectively connect to contact points 1 to 5, the second end can selectively connect to contact points 3 to 7, the third end can selectively connect to contact points 8 to 12, and the fourth end can selectively connect to contact points 10 to 14.

[0070] like Figure 5 As shown, the first end connected to contact point 1, the second end connected to contact point 3, and the third end connected to contact point 8 and the fourth end connected to contact point 10 are defined as the first gear.

[0071] like Figure 6 As shown, the first end connected to contact point 2, the second end connected to contact point 4, and the third end connected to contact point 9 and the fourth end connected to contact point 11 are defined as the second gear.

[0072] like Figure 7 As shown, the first end connected to contact point 3, the second end connected to contact point 5, the third end connected to contact point 10, and the fourth end connected to contact point 12 are defined as the third gear.

[0073] like Figure 8 As shown, the first end connected to contact point 4 and the second end connected to contact point 6 are defined as the same, while the third end connected to contact point 11 and the fourth end connected to contact point 13 are defined as the fourth gear.

[0074] like Figure 9 As shown, the fifth gear is defined as follows: the first end is connected to contact point 5, the second end is connected to contact point 7, and the third end is connected to contact point 12 and the fourth end is connected to contact point 14.

[0075] If the adjustment groove 22 extends in the front-to-back direction, the positions are defined as the first to the fifth gear from front to back; if the adjustment groove 22 extends in the left-to-right direction, the positions are defined as the first to the fifth gear from left to right.

[0076] The audio output plug 10 is located at the front of the housing 20. Preferably, the audio output plug 10 extends into the housing 20 via a cable 11 and is connected to the multi-position impedance manual adjustment circuit 40 of the circuit board 21.

[0077] The audio input jack 30 is located inside the housing 20, with its insertion port exposed on the rear side of the housing 20. Preferably, the audio input jack 30 is mounted on the circuit board 21 and connected to the multi-position impedance manual adjustment circuit 40 of the circuit board 21. Preferably, the audio input jack 30 is a 4.4mm audio input jack 30, with pin 4 grounded through resistor R11, pin 2 grounded through resistor R12, pins 1 and 5 grounded, and the grounding pin GND of the audio output plug 10 grounded.

[0078] like Figure 10 As shown, in another embodiment, the impedance matching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor;

[0079] Multi-position toggle switches include double-pole switches (such as...) Figure 10 The double-pole switch SW1 and contacts 1 to 14 are connected to contacts 8 and 1 respectively. The other end of the two knife switches of the double-pole switch can be selectively connected to contacts 14 and 7, or contacts 13 and 6, or contacts 12 and 5, or contacts 11 and 4, or contacts 10 and 3, or contacts 9 and 2. Contacts 8 and 1 are respectively connected to the positive terminals of the left and right channels of the audio output plug.

[0080] Each of the first to fifth resistors has two resistors. Contact 14 is connected to the positive terminal of the left channel of the audio input jack, and contact 13 is connected to one of the first resistors (e.g., Figure 10 The middle resistor R1 is connected to the positive terminal of the left channel of the audio input jack, and contact 12 is connected through one of the second resistors (such as...). Figure 10 The middle resistor R2) is connected to the positive terminal of the left channel of the audio input jack, and contact 11 is connected through one of the third resistors (such as...). Figure 10 The middle resistor R3) is connected to the positive terminal of the left channel of the audio input jack, and contact 10 is connected through one of the fourth resistors (such as...). Figure 10 The middle resistor R4 is connected to the positive terminal of the left channel of the audio input jack, and contact 9 is connected through one of the fifth resistors (such as...). Figure 10 Connect the medium resistor R5 to the positive terminal of the left channel of the audio input jack;

[0081] Contact 7 connects to the positive terminal of the right channel of the audio input jack, and contact 6 connects to another first resistor (such as...). Figure 10 The middle resistor R6 is connected to the positive terminal of the right channel of the audio input jack, and contact 5 is connected to another second resistor (such as...). Figure 10 The middle resistor R7 is connected to the positive terminal of the right channel of the audio input jack, and contact 4 is connected to another third resistor (such as...). Figure 10 The middle resistor R8 is connected to the positive terminal of the right channel of the audio input jack, and contact 3 is connected to another fourth resistor (such as...). Figure 10 The middle resistor R91 is connected to the positive terminal of the right channel of the audio input jack, and contact 2 is connected to another fifth resistor (such as...). Figure 10 The medium resistor R10 is connected to the positive terminal of the right channel of the audio input jack.

[0082] Define the other end of the two knife switches of the double switch as the first position, connected to contact 14 and contact 7. At this time, the positive terminal of the left channel of the audio input jack is connected to the positive terminal of the left channel of the audio output plug 10 through contact 14, the knife switch connected to contact 14, and contact 8 in sequence. At the same time, the positive terminal of the right channel of the audio input jack is connected to the positive terminal of the right channel of the audio output plug 10 through contact 7, the knife switch connected to contact 7, and contact 1 in sequence.

[0083] Define the other ends of the two knife switches of the double-pole switch as the second position, connected to contacts 13 and 6. In this position, the positive terminal of the left channel of the audio input jack passes through one of the first resistors (e.g., Figure 10 The resistor R1), contact 13, the knife switch connected to contact 13, and contact 8 are connected to the positive terminal of the left channel of the audio output plug 10. Simultaneously, the positive terminal of the right channel of the audio input jack is connected sequentially through another first resistor (such as...). Figure 10 The medium resistor R6), contact 6, the knife switch connected to contact 6, and contact 1 are connected to the positive terminal of the right channel of the audio output plug 10.

[0084] Define the other ends of the two knife switches of the double-pole switch as the third position, connected to contacts 12 and 5. In this position, the positive terminal of the left channel of the audio input jack passes through one of the second resistors (e.g., Figure 10 The medium resistor R2), contact 12, the knife switch connected to contact 12, and contact 8 are connected to the positive terminal of the left channel of the audio output plug 10. Simultaneously, the positive terminal of the right channel of the audio input jack is connected to another second resistor (such as...). Figure 10 The medium resistor R7), contact 5, the knife switch connected to contact 5, and contact 1 are connected to the positive terminal of the right channel of the audio output plug 10.

[0085] Define the other ends of the two knife switches of the double-pole switch as the fourth position, connected to contacts 11 and 4. In this position, the positive terminal of the left channel of the audio input jack passes through one of the third resistors (e.g., Figure 10 The audio output plug 10 is connected to the left channel positive terminal via a resistor R3, contact 11, a knife switch connected to contact 11, and contact 8. Simultaneously, the right channel positive terminal of the audio input plug is connected to another third resistor (such as...). Figure 10 The medium resistor R8), contact 4, the knife switch connected to contact 4, and contact 1 are connected to the positive terminal of the right channel of the audio output plug 10.

[0086] Define the other ends of the two knife switches of the double-pole switch as the fifth position, connected to contacts 10 and 3. In this position, the positive terminal of the left channel of the audio input jack passes through one of the fourth resistors (e.g., Figure 10 The audio output plug 10 is connected to the left channel positive terminal of the audio output plug 10 via a resistor R4, contact 10, a knife switch connected to contact 10, and contact 8. Simultaneously, the right channel positive terminal of the audio input plug is connected to another fourth resistor (such as...). Figure 10 The medium resistor R9), contact 3, the knife switch connected to contact 3, and contact 1 are connected to the positive terminal of the right channel of the audio output plug 10.

[0087] Define the other ends of the two knife switches of the double-pole switch as the sixth position, connected to contacts 9 and 2. In this position, the positive terminal of the left channel of the audio input jack passes sequentially through one of the fifth resistors (e.g., ...). Figure 10 The medium resistor R5), contact 9, the knife switch connected to contact 9, and contact 8 are connected to the positive terminal of the left channel of the audio output plug 10. Simultaneously, the positive terminal of the right channel of the audio input jack is connected sequentially through another fifth resistor (such as...). Figure 10 The medium resistor R10), contact 2, the knife switch connected to contact 2, and contact 1 are connected to the positive terminal of the right channel of the audio output plug 10.

[0088] In this embodiment, taking the adjustment groove 22 extending in the front-to-back direction as an example, the working principle will be roughly explained below:

[0089] By default, such as Figure 5 As shown, in the first position, the positive terminal of the left channel of the audio input jack 30 is connected to the positive terminal of the left channel of the audio output plug 10 via contact 3, the second terminal, the first terminal, and contact 1 in sequence. Simultaneously, the positive terminal of the right channel of the audio input jack 30 is connected to the positive terminal of the right channel of the audio output plug 10 via contact 10, the fourth terminal, the third terminal, and contact 8 in sequence. At this time, there is no impedance between the audio input jack 30 and the audio output plug 10, i.e., zero impedance and high sensitivity, suitable for low-power audio playback devices such as portable music players.

[0090] If a high-power audio playback device is needed at this time, the user can slide the toggle block 412 down to move the toggle key 411 down until it reaches the fifth position.

[0091] like Figure 9 As shown, in the fifth position, the positive terminal of the left channel of the audio input jack 30 is connected to the positive terminal of the left channel of the audio output plug 10 via the fourth resistor (resistor R4 in the figure), contact 7, the second terminal, the first terminal, contact 5, and the second resistor (resistor R2 in the figure). Simultaneously, the positive terminal of the right channel of the audio input jack 30 is connected to the positive terminal of the right channel of the audio output plug 10 via the fourth resistor (resistor R9 in the figure), contact 14, the second terminal, the first terminal, contact 12, and the second resistor (resistor R7 in the figure). At this time, there is a high impedance between the audio input jack 30 and the audio output plug 10, i.e., high impedance and low sensitivity, suitable for high-power audio playback devices.

[0092] In summary, the key design feature of this utility model is that by setting a multi-level impedance manual adjustment circuit between the audio output plug and the audio input socket, the impedance can be manually adjusted according to usage requirements, providing good flexibility and preventing over-driving of headphones, thus extending their service life.

[0093] Secondly, through the specific circuit structure of the multi-level impedance manual adjustment circuit, the five-level impedance adjustment is maximized, which can then be adapted to a variety of playback devices with different output power, making it highly versatile.

[0094] Furthermore, the adjustable groove's left-right and front-back structural design can accommodate different user habits.

[0095] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the technical scope of the present utility model.

Claims

1. An impedance-adjustable audio adapter for use between headphones and a playback device, characterized in that: It includes a housing, an audio output plug, and an audio input jack; Of the audio output plug and audio input jack, one is used to connect headphones and the other is used to connect a playback device. The housing is equipped with a multi-position manual impedance adjustment circuit for manually adjusting the audio impedance. The audio output plug is connected to the audio input socket via a multi-position impedance manual adjustment circuit.

2. The impedance-adjusting audio adapter of claim 1, wherein: The multi-position impedance manual adjustment circuit includes a multi-position toggle switch and an impedance matching circuit connected together, and the audio output plug is connected to the audio input socket through the multi-position toggle switch and the impedance matching circuit.

3. The impedance matching audio adapter of claim 2, wherein: The impedance matching circuit includes a first resistor, a second resistor, a third resistor, and a fourth resistor; The multi-position toggle switch has a toggle key and contacts 1 to 14. Contacts 1 and 2 are connected to the positive terminal of the left channel of the audio output plug, contact 3 is connected to the positive terminal of the left channel of the audio input jack, contacts 8 and 9 are connected to the positive terminal of the right channel of the audio output plug, and contact 310 is connected to the positive terminal of the right channel of the audio input jack. Each of the first to fourth resistors has two resistors. Contact 4 is connected to the positive left channel of the audio input jack through one of the first resistors. Contact 5 is connected to the positive left channel of the audio output plug through one of the second resistors. Contact 6 is connected to the positive left channel of the audio output plug through one of the third resistors. Contact 7 is connected to the positive left channel of the audio input jack through one of the fourth resistors. Contact 11 is connected to the positive left channel of the audio input jack through another first resistor; contact 12 is connected to the positive left channel of the audio output plug through another second resistor; contact 13 is connected to the positive left channel of the audio output plug through another third resistor; and contact 14 is connected to the positive left channel of the audio input jack through another fourth resistor. The toggle key has a first end, a second end, a third end, and a fourth end. The first end and the second end are connected, and the third end and the fourth end are connected. The first end can be selectively connected to contact points 1 to 5, the second end can be selectively connected to contact points 3 to 7, the third end can be selectively connected to contact points 8 to 12, and the fourth end can be selectively connected to contact points 10 to 14.

4. The impedance matching audio adapter of claim 3, wherein: The resistance values ​​of the first, second, third, and fourth resistors are not the same; the resistance values ​​of the two first resistors are the same; the resistance values ​​of the two second resistors are the same; the resistance values ​​of the two third resistors are the same; and the resistance values ​​of the two fourth resistors are the same.

5. The impedance matching audio adapter of claim 2, wherein: The impedance matching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; The multi-position toggle switch has a double-pole switch and contacts 1 to 14. One end of each of the two knife switches of the double-pole switch is connected to contact 8 and contact 1 respectively. By toggling the double-pole switch, the other end of each of the two knife switches can be selectively connected to contact 14 and contact 7, or to contact 13 and contact 6, or to contact 12 and contact 5, or to contact 11 and contact 4, or to contact 10 and contact 3, or to contact 9 and contact 2. Contact 8 and contact 1 are respectively connected to the positive terminals of the left and right channels of the audio output plug. Each of the first to fifth resistors has two resistors. Contact 14 is connected to the positive terminal of the left channel of the audio input jack. Contact 13 is connected to the positive terminal of the left channel of the audio input jack through one of the first resistors. Contact 12 is connected to the positive terminal of the left channel of the audio input jack through one of the second resistors. Contact 11 is connected to the positive terminal of the left channel of the audio input jack through one of the third resistors. Contact 10 is connected to the positive terminal of the left channel of the audio input jack through one of the fourth resistors. Contact 9 is connected to the positive terminal of the left channel of the audio input jack through one of the fifth resistors. Contact 7 is connected to the positive terminal of the right channel of the audio input jack. Contact 6 is connected to the positive terminal of the right channel of the audio input jack through another first resistor. Contact 5 is connected to the positive terminal of the right channel of the audio input jack through another second resistor. Contact 4 is connected to the positive terminal of the right channel of the audio input jack through another third resistor. Contact 3 is connected to the positive terminal of the right channel of the audio input jack through another fourth resistor. Contact 2 is connected to the positive terminal of the right channel of the audio input jack through another fifth resistor.

6. The impedance matching audio adapter of claim 3, wherein: The audio output plug is located at the front of the housing, and the audio input socket is located inside the housing with the insertion port of the audio input socket exposed on the rear side of the housing.

7. The impedance matching audio adapter of claim 6, wherein: The multi-position toggle switch also has a toggle block for moving the toggle key when toggled; A circuit board is provided inside the housing, the multi-position impedance manual adjustment circuit is provided on the circuit board, and the toggle block of the multi-position toggle switch extends out of the upper end surface of the housing. The audio output plug is connected to the multi-position impedance manual adjustment circuit of the circuit board via a wire extending into the housing. The audio input socket is located on the circuit board and is connected to the multi-position impedance manual adjustment circuit of the circuit board.

8. The impedance matching audio adapter of claim 7, wherein: The upper end face of the housing is provided with an adjustment groove for the displacement of the actuating block, and the actuating block is slidably mounted in the adjustment groove.

9. The impedance matching audio adapter of claim 8, wherein: The adjustment groove extends in the front-to-back direction, and the multi-position toggle switch is located on the left or right side of the audio input jack.

10. The impedance matching audio adapter of claim 8, wherein: The adjustment slot extends in the left and right direction, and the multi-position toggle switch is located in front of the audio input jack.

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