JP2012231348A - Amplifier - Google Patents

Amplifier Download PDF

Info

Publication number
JP2012231348A
JP2012231348A JP2011098934A JP2011098934A JP2012231348A JP 2012231348 A JP2012231348 A JP 2012231348A JP 2011098934 A JP2011098934 A JP 2011098934A JP 2011098934 A JP2011098934 A JP 2011098934A JP 2012231348 A JP2012231348 A JP 2012231348A
Authority
JP
Japan
Prior art keywords
amplifier
constant voltage
ground
signal
line
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2011098934A
Other languages
Japanese (ja)
Other versions
JP5633073B2 (en
Inventor
Yoshihisa Shiotani
好古 塩谷
Masatoshi Toyama
雅利 遠山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Korg Inc
Original Assignee
Korg Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Korg Inc filed Critical Korg Inc
Priority to JP2011098934A priority Critical patent/JP5633073B2/en
Publication of JP2012231348A publication Critical patent/JP2012231348A/en
Application granted granted Critical
Publication of JP5633073B2 publication Critical patent/JP5633073B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

PROBLEM TO BE SOLVED: To provide a device that further reduces noise effects of electromagnetic induction and the like on sound quality in a simpler configuration.SOLUTION: Although when a DC voltage from a constant voltage circuit 1 is power-supplied to a constant voltage circuit 10 of an external apparatus 200 via a constant voltage supply line 50 and a constant voltage ground line 51, a ground loop is formed through the constant voltage ground line 51, a gnd section 15 providing a ground point in the external apparatus, a signal ground line 56 and a gnd section 2 providing a ground point in the amplifier to cause noise, an operation of a switch 5 disconnects an inverting terminal of an operational amplifier 3 and the ground point (gnd section 2) from each other to eliminate the ground loop. This can reduce noise to prevent a sound quality deterioration.

Description

本発明は、オーディオシステムを構成する外部機器に電源供給を行うアンプの改良に関する。   The present invention relates to an improvement of an amplifier that supplies power to an external device constituting an audio system.

アンプに搭載した電源トランスの出力を、他の機器に搭載された整流回路に直接接続し、更にアース線を整流用アース、定電圧用アース、信号用アースに分離して各機器に接続し、各機器の内の１機器内で上記３本のアース線を、いわゆる一点アースとする構成の装置が提案されている（例えば、特許文献１参照。）。この発明によれば、各機器に２次トランスを設けずに済みこと等から、コスト低減等を図ることができると共に、ハム等での雑音による音質劣化を低減することが可能になる。 Connect the output of the power transformer mounted on the amplifier directly to the rectifier circuit mounted on other equipment, and further connect the ground wire to rectifier ground, constant voltage ground, signal ground and connect to each equipment, An apparatus has been proposed in which the above three ground wires are so-called single-point grounds in one of the devices (see, for example, Patent Document 1). According to the present invention, since it is not necessary to provide a secondary transformer in each device, it is possible to reduce costs and the like, and it is possible to reduce deterioration in sound quality due to noise caused by hum or the like.

特開平５−１２１９５６号公報（第２−３頁、第１図）Japanese Patent Laid-Open No. 5-121956 (page 2-3, FIG. 1)

しかしながら、上記発明によれば、各機器に２次トランスを設けずに済む代わりに、定電圧用アースおよび信号用アースの他に整流用アースが必要であり、より簡易な構成で電磁誘導等による音質への外来ノイズの影響を低減することが望まれていた。   However, according to the above invention, instead of providing a secondary transformer in each device, a rectifying ground is required in addition to a constant voltage ground and a signal ground. It has been desired to reduce the influence of external noise on sound quality.

本発明は、かかる従来の課題を解決するためになされたもので、より簡素な構成で電磁誘導等による音質へのノイズの影響を一層低減させる装置を提供することを目的とする。   The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an apparatus that can further reduce the influence of noise on sound quality due to electromagnetic induction or the like with a simpler configuration.

上記目的を達成するために、本発明は、オーディオシステム（３００）を構成する外部機器（２００）から出力される音楽信号を、信号線（５５）およびこれとペアになる信号用アース線（５６）を介して入力するアンプ（１００）であって、
前記信号線（５５）を自身の非反転端子、前記信号用アース線を自身の反転端子に夫々接続された演算増幅器（３）と、この演算増幅器（３）の出力信号を増幅する電力増幅器（４）と、電源供給を受けて所定値の直流電圧を出力する定電圧回路（１）と、前記反転端子と当該アンプ内の接地点（２）との間に設けられ、前記反転端子と前記接地点との導通・非導通を選択可能なスイッチ（５）とを備え、
前記定電圧回路（１）からの直流電圧を定電圧供給線（５０）およびこれとペアになる定電圧用アース線（５１）を介して外部機器（２００）側の定電圧回路（１０）に電源供給する場合、前記スイッチ（５）の操作によって前記反転端子と前記接地点とが非導通状態となることを特徴とした。 In order to achieve the above object, the present invention provides a music signal output from an external device (200) constituting the audio system (300) as a signal line (55) and a signal ground line (56) paired therewith. ) Through the amplifier (100),
An operational amplifier (3) in which the signal line (55) is connected to its own non-inverting terminal and the signal ground line is connected to its inverting terminal, and a power amplifier (amplifying the output signal of the operational amplifier (3)) 4), a constant voltage circuit (1) that receives a power supply and outputs a DC voltage of a predetermined value, and is provided between the inverting terminal and a ground point (2) in the amplifier, the inverting terminal and the A switch (5) capable of selecting conduction / non-conduction with the ground point,
The DC voltage from the constant voltage circuit (1) is transferred to the constant voltage circuit (10) on the external device (200) side through the constant voltage supply line (50) and the constant voltage ground line (51) paired therewith. When power is supplied, the operation of the switch (5) causes the inverting terminal and the grounding point to be in a non-conductive state.

この発明によれば、定電圧回路（１）からの直流電圧を定電圧供給線（５０）およびこれとペアになる定電圧用アース線（５１）を介して外部機器（２００）側の定電圧回路（１０）に電源供給する場合、定電圧用アース線（５１）、外部機器内の接地点（１５）、信号用アース線（５６）およびアンプ内の接地点（２）を通るグランドループが形成されてノイズの原因になるが、スイッチ（５）の操作によって、演算増幅器（３）の反転端子と接地点（２）とが非導通状態となって、グランドループが形成されないことになる。この結果、ノイズが低減され音質劣化を防止することが可能になる。   According to the present invention, the DC voltage from the constant voltage circuit (1) is supplied to the constant voltage on the external device (200) side via the constant voltage supply line (50) and the constant voltage ground line (51) paired therewith. When power is supplied to the circuit (10), a ground loop that passes through the constant voltage ground wire (51), the ground point (15) in the external device, the signal ground wire (56), and the ground point (2) in the amplifier. Although it is formed and causes noise, the operation of the switch (5) causes the inverting terminal of the operational amplifier (3) and the grounding point (2) to be in a non-conductive state, so that a ground loop is not formed. As a result, noise can be reduced and deterioration of sound quality can be prevented.

本発明によれば、より簡素な構成で電磁誘導等による音質へのノイズの影響を一層低減させる装置を実現することができるという効果が得られる。   According to the present invention, it is possible to realize an apparatus that can further reduce the influence of noise on sound quality due to electromagnetic induction or the like with a simpler configuration.

オーディオシステム３００の構成図である。1 is a configuration diagram of an audio system 300. FIG. 本発明の実施形態における作用の説明図である。It is explanatory drawing of the effect | action in embodiment of this invention.

以下、本発明の実施の形態について図面を参照しつつ説明する。本発明の実施の形態では、オーディオシステム３００を構成する外部機器２００の一例として電子楽器等の音源からの音楽信号がアンプ１００に送られる例について説明する。なお、外部機器としてはイフェクタ等の音楽装置であって、楽音信号に効果付加したものを音楽信号として出力するもの等様々なものを採用できる。   Embodiments of the present invention will be described below with reference to the drawings. In the embodiment of the present invention, an example in which a music signal from a sound source such as an electronic musical instrument is sent to the amplifier 100 as an example of the external device 200 configuring the audio system 300 will be described. As the external device, various devices such as an effector or the like that outputs an effect added to a musical sound signal as a music signal can be adopted.

（構成）
図１は本発明の実施形態であるアンプ１００と外部機器２００とを有して成るオーディオシステム３００の構成図である。アンプ１００は、プラグ７が、例えば家庭用コンセントに差し込まれて１００（Ｖ）の交流電圧が供給された場合、例えば９（Ｖ）の所定値の直流電圧を出力する定電圧回路１と、演算増幅器３と、演算増幅器３の出力に接続され演算増幅器３からの信号を増幅する電力増幅器（パワーアンプ）４と、この電力増幅器４に接続されたスピーカ６と、スイッチ５とを有して構成されている。定電圧回路１からは、定電圧供給線５０とこれとペアになる定電圧用アース線５１とが伸びている。例えば、この定電圧供給線５０と定電圧用アース線５１とは互いに絶縁された状態で被覆され一本のケーブル５３となっている。 (Constitution)
FIG. 1 is a configuration diagram of an audio system 300 including an amplifier 100 and an external device 200 according to an embodiment of the present invention. The amplifier 100 is connected to the constant voltage circuit 1 that outputs a DC voltage having a predetermined value of 9 (V), for example, when the plug 7 is inserted into a household outlet and supplied with an AC voltage of 100 (V), for example. An amplifier 3, a power amplifier (power amplifier) 4 connected to the output of the operational amplifier 3 to amplify a signal from the operational amplifier 3, a speaker 6 connected to the power amplifier 4, and a switch 5 Has been. From the constant voltage circuit 1, a constant voltage supply line 50 and a constant voltage ground line 51 paired therewith extend. For example, the constant voltage supply line 50 and the constant voltage ground line 51 are covered with each other in a state of being insulated from each other to form a single cable 53.

演算増幅器３と電力増幅器４の電源供給は定電圧回路１から行われている。また、演算増幅器３と電力増幅器４との接地は、アンプ１００の内部の接地点であるｇｎｄ部２で行われており、これらの電源供給や接地を行うため必要な配線がなされている。また、端子６０、端子６１は、夫々、信号線５５、信号用アース線５６を接続するためのものであり、信号線５５と信号用アース線５６とはペアになってケーブル５７を形成している。例えば、信号線５５と信号用アース線５６とは互いに絶縁された状態で被覆され一本のケーブル５７となっている。なお、ｇｎｄ部２はアンプ１００の筺体（ケース）でとることができる。   The constant voltage circuit 1 supplies power to the operational amplifier 3 and the power amplifier 4. Further, the operational amplifier 3 and the power amplifier 4 are grounded at the gnd unit 2 which is a grounding point inside the amplifier 100, and necessary wirings are provided for power supply and grounding. The terminal 60 and the terminal 61 are for connecting the signal line 55 and the signal ground line 56, respectively. The signal line 55 and the signal ground line 56 are paired to form a cable 57. Yes. For example, the signal line 55 and the signal ground line 56 are covered with each other while being insulated from each other to form a single cable 57. The gnd unit 2 can be a casing of the amplifier 100.

また、演算増幅器３の非反転端子には信号線５５が電気的に接続され、また、演算増幅器３の反転端子には信号用アース線５６が電気的に接続されている。かくして、外部機器２００から出力される音楽信号は、信号線５５およびこれとペアになる信号用アース線５６を介してアンプ１００の演算増幅器３に入力される。そして、演算増幅器３の反転端子とアンプ２００内の接地点であるｇｎｄ部２との間にはスイッチ５が設けられており、演算増幅器３の反転端子とｇｎｄ部２との導通・非導通を選択操作可能に構成されている。 The signal line 55 is electrically connected to the non-inverting terminal of the operational amplifier 3, and the signal ground line 56 is electrically connected to the inverting terminal of the operational amplifier 3. Thus, the music signal output from the external device 200 is input to the operational amplifier 3 of the amplifier 100 via the signal line 55 and the signal ground line 56 paired therewith. A switch 5 is provided between the inverting terminal of the operational amplifier 3 and the gnd unit 2 which is a ground point in the amplifier 200, and the inverting terminal of the operational amplifier 3 and the gnd unit 2 are connected / disconnected. It is configured to be selectable.

一方、オーディオシステム３００を構成する外部機器２００は、端子６５、端子６６を介して夫々、定電圧供給線５０と定電用アース線５１とが電気的に接続されている。そして、外部機器２００側の定電圧回路１０に電源供給される。電源供給を受けた定電圧回路１０は、所定値例えば６（Ｖ）の直流電圧を出力して機器内の所要の箇所に電源供給する。この例では増幅器１２が電源供給されている。この増幅器１２は音源１１から出力される音楽信号を増幅して出力する。   On the other hand, in the external device 200 constituting the audio system 300, the constant voltage supply line 50 and the constant voltage ground line 51 are electrically connected via the terminal 65 and the terminal 66, respectively. Then, power is supplied to the constant voltage circuit 10 on the external device 200 side. The constant voltage circuit 10 that has received power supply outputs a DC voltage of a predetermined value, for example, 6 (V), and supplies power to a required location in the device. In this example, the amplifier 12 is supplied with power. The amplifier 12 amplifies the music signal output from the sound source 11 and outputs it.

また、端子６８、端子６９によって信号線５５、信号用アース線５６が接続されており、更に、外部機器２００内の接地点であるｇｎｄ部１５には、定電圧用アース線５１と、信号用アース線５６とが電気的に接続されている。そして、外部機器２００から出力される音楽信号（この例では音源１１の出力を増幅器１２で増幅した信号）を、信号線５５および信号用アース線５６を介してアンプ１００側に送る。これにより、音楽信号がアンプ２００側で電力増幅器４によって増幅されてスピーカ６から放音される。なお、ｇｎｄ部１５は外部機器２００の筺体（ケース）でとることができる。 Further, the signal line 55 and the signal ground line 56 are connected by the terminal 68 and the terminal 69, and the constant voltage ground line 51 and the signal ground line 51 are connected to the gnd portion 15 which is a ground point in the external device 200. The ground wire 56 is electrically connected. Then, a music signal output from the external device 200 (in this example, a signal obtained by amplifying the output of the sound source 11 by the amplifier 12) is sent to the amplifier 100 via the signal line 55 and the signal ground line 56. As a result, the music signal is amplified by the power amplifier 4 on the amplifier 200 side and emitted from the speaker 6. The gnd unit 15 can be a casing of the external device 200.

（作用）
次に作用について説明する。アンプ１００から伸びる定電圧供給線５０と、定電圧用アース線５１とを、外部機器２００の端子６５、端子６６に接続しない場合には、スイッチ５を選択操作して、アンプ１００の演算増幅器３の反転端子とｇｎｄ部２（接地点）とを導通状能としておいてもグランドループ（接地点を通るノイズ発生ループのこと）は形成されない。しかしながら、アンプ１００から伸びる定電圧供給線５０と定電圧用アース線５１とを、外部機器２００の端子６５、端子６６に接続した場合には、グランドループが形成されてしまうことになる。 (Function)
Next, the operation will be described. When the constant voltage supply line 50 extending from the amplifier 100 and the constant voltage ground line 51 are not connected to the terminal 65 and the terminal 66 of the external device 200, the switch 5 is selected and the operational amplifier 3 of the amplifier 100 is selected. Even if the inversion terminal and the gnd portion 2 (grounding point) are made conductive, a ground loop (a noise generation loop passing through the grounding point) is not formed. However, when the constant voltage supply line 50 and the constant voltage ground line 51 extending from the amplifier 100 are connected to the terminals 65 and 66 of the external device 200, a ground loop is formed.

図２は点線（符号Ａで示す）でグランドループが形成された状態を示す説明図である。定電圧用アース線５１、外部機器２００内の接地点であるｇｎｄ部１５、信号用アース線５６および導通状態のスイッチ５、および、アンプ内の接地点であるｇｎｄ部２を通るグランドループが形成され、これがノイズの原因になる。しかしながら、スイッチ５の操作によって、演算増幅器３の反転端子と接地点（ｇｎｄ部２）とを非導通状態とすると、グランドループが形成されないことになる。この結果、ノイズが低減され音質劣化を防止することが可能になる。なお、本発明の実施形態のアンプ１００の定電圧回路１から伸びるケーブル５３を接続せず外部機器２００に電源供給を行わない場合（例えば、外部機器２００が内部電池で動作する場合等）、スイッチ５を導通状態とした方がノイズが低減されるためスイッチ５を導通・非導通選択可能としている。よって、このスイッチ５を設けることにより、外部機器２００の電源供給態様の選択の幅を増やすことができる。 FIG. 2 is an explanatory diagram showing a state in which a ground loop is formed by a dotted line (indicated by reference symbol A). A ground loop for passing through the constant voltage ground wire 51, the gnd portion 15 that is a ground point in the external device 200, the signal ground wire 56 and the conductive switch 5, and the gnd portion 2 that is the ground point in the amplifier is formed. This causes noise. However, if the inverting terminal of the operational amplifier 3 and the ground point (gnd portion 2) are brought into a non-conducting state by the operation of the switch 5, a ground loop is not formed. As a result, noise can be reduced and deterioration of sound quality can be prevented. When the cable 53 extending from the constant voltage circuit 1 of the amplifier 100 according to the embodiment of the present invention is not connected and power is not supplied to the external device 200 (for example, when the external device 200 operates with an internal battery), the switch Since the noise is reduced when 5 is turned on, the switch 5 can be selected to be conductive or non-conductive. Therefore, by providing this switch 5, the range of selection of the power supply mode of the external device 200 can be increased.

以上説明してきたように、本発明の実施形態によれば、アンプ１００内の演算増幅器３の反転端子とアンプ２００内の接地点であるｇｎｄ部２との間にスイッチ５を設け、演算増幅器３の反転端子とアンプ２００内の接地点であるｇｎｄ部２との導通・非導通を選択操作可能としたので、アンプ１００から伸びる定電圧供給線５０と、定電圧用アース線５１とを、外部機器２００の端子６５、端子６６に接続した場合であってもグランドループの形成を阻止することができる。この結果、極めて簡単な構成で電磁誘導等による音質へのノイズの影響を一層低減させることが可能になる。   As described above, according to the embodiment of the present invention, the switch 5 is provided between the inverting terminal of the operational amplifier 3 in the amplifier 100 and the gnd unit 2 that is the ground point in the amplifier 200. Since the continuity / non-conduction between the inverting terminal of the amplifier 200 and the gnd portion 2 which is the ground point in the amplifier 200 can be selected, the constant voltage supply line 50 extending from the amplifier 100 and the constant voltage ground line 51 are connected to the outside. Even when connected to the terminals 65 and 66 of the device 200, formation of a ground loop can be prevented. As a result, it is possible to further reduce the influence of noise on sound quality due to electromagnetic induction or the like with a very simple configuration.

以上説明してきたように、オーディオ分野等に利用することができる。   As described above, it can be used in the audio field and the like.

１ 定電圧回路
３ 演算増幅器
４ 電力増幅器
５ スイッチ
６ スピーカ
１０ 定電圧回路
１１ 音源
１２ 増幅器
５０ 定電圧供給線
５１ 定電圧用アース線
５５ 信号線
５６ 信号用アース線 DESCRIPTION OF SYMBOLS 1 Constant voltage circuit 3 Operational amplifier 4 Power amplifier 5 Switch 6 Speaker 10 Constant voltage circuit 11 Sound source 12 Amplifier 50 Constant voltage supply line 51 Constant voltage ground line 55 Signal line 56 Signal ground line

Claims (2)

オーディオシステムを構成する外部機器から出力される音楽信号を、信号線およびこれとペアになる信号用アース線を介して入力するアンプであって、
前記信号線を自身の非反転端子、前記信号用アース線を自身の反転端子に夫々接続された演算増幅器と、この演算増幅器の出力信号を増幅する電力増幅器と、電源供給を受けて所定値の直流電圧を出力する定電圧回路と、前記反転端子と当該アンプ内の接地点との間に設けられ、前記反転端子と前記接地点との導通・非導通を選択可能なスイッチとを備え、
前記定電圧回路からの直流電圧を定電圧供給線およびこれとペアになる定電圧用アース線を介して外部機器側の定電圧回路に電源供給する場合、前記スイッチの操作によって前記反転端子と前記接地点とが非導通状態となることを特徴としたアンプ。 An amplifier for inputting a music signal output from an external device constituting an audio system via a signal line and a signal ground line paired therewith,
An operational amplifier in which the signal line is connected to its own non-inverting terminal and the signal ground line is connected to its own inverting terminal; a power amplifier that amplifies the output signal of the operational amplifier; A constant voltage circuit that outputs a DC voltage; a switch provided between the inverting terminal and a ground point in the amplifier; and a switch capable of selecting conduction / non-conduction between the inverting terminal and the ground point;
When supplying the DC voltage from the constant voltage circuit to the constant voltage circuit on the side of the external device through the constant voltage supply line and the constant voltage ground wire paired therewith, the inverting terminal and the An amplifier characterized by being in a non-conducting state with a grounding point. 請求項１に記載のアンプにおいて、
前記電力増幅器にはスピーカが接続されていることを特徴とするアンプ。 The amplifier according to claim 1,
An amplifier, wherein a speaker is connected to the power amplifier.
JP2011098934A 2011-04-27 2011-04-27 Amplifier Expired - Fee Related JP5633073B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011098934A JP5633073B2 (en) 2011-04-27 2011-04-27 Amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2011098934A JP5633073B2 (en) 2011-04-27 2011-04-27 Amplifier

Publications (2)

Publication Number Publication Date
JP2012231348A true JP2012231348A (en) 2012-11-22
JP5633073B2 JP5633073B2 (en) 2014-12-03

Family

ID=47432531

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2011098934A Expired - Fee Related JP5633073B2 (en) 2011-04-27 2011-04-27 Amplifier

Country Status (1)

Country Link
JP (1) JP5633073B2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014180994A1 (en) * 2013-05-10 2014-11-13 Jürgen Amann Audio switchover apparatus
JP2015012626A (en) * 2013-06-26 2015-01-19 三菱電機株式会社 Power supply device
JP2015157696A (en) * 2014-02-25 2015-09-03 日立住友重機械建機クレーン株式会社 Signal processing device of construction machinery, and overload protector of construction machinery
EP3787176A4 (en) * 2018-04-27 2022-01-19 Hitachi-Johnson Controls Air Conditioning, Inc. Inverter device, air conditioner, and ground connection method for inverter device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02120941U (en) * 1989-03-15 1990-10-01
JPH0318129A (en) * 1989-05-01 1991-01-25 Audio Technol Inc Balanced output circuit
JP2003045696A (en) * 2001-07-30 2003-02-14 Kenwood Corp Antistatic circuit
JP2006148837A (en) * 2004-11-25 2006-06-08 Sanyo Electric Co Ltd Acoustic/video playback system
JP2007324787A (en) * 2006-05-31 2007-12-13 New Japan Radio Co Ltd Signal processing circuit
WO2008114357A1 (en) * 2007-03-16 2008-09-25 Pioneer Corporation Electronic device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02120941U (en) * 1989-03-15 1990-10-01
JPH0318129A (en) * 1989-05-01 1991-01-25 Audio Technol Inc Balanced output circuit
JP2003045696A (en) * 2001-07-30 2003-02-14 Kenwood Corp Antistatic circuit
JP2006148837A (en) * 2004-11-25 2006-06-08 Sanyo Electric Co Ltd Acoustic/video playback system
JP2007324787A (en) * 2006-05-31 2007-12-13 New Japan Radio Co Ltd Signal processing circuit
WO2008114357A1 (en) * 2007-03-16 2008-09-25 Pioneer Corporation Electronic device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014180994A1 (en) * 2013-05-10 2014-11-13 Jürgen Amann Audio switchover apparatus
JP2015012626A (en) * 2013-06-26 2015-01-19 三菱電機株式会社 Power supply device
JP2015157696A (en) * 2014-02-25 2015-09-03 日立住友重機械建機クレーン株式会社 Signal processing device of construction machinery, and overload protector of construction machinery
EP3787176A4 (en) * 2018-04-27 2022-01-19 Hitachi-Johnson Controls Air Conditioning, Inc. Inverter device, air conditioner, and ground connection method for inverter device

Also Published As

Publication number Publication date
JP5633073B2 (en) 2014-12-03

Similar Documents

Publication Publication Date Title
US9237401B2 (en) Electronic devices with adjustable bias impedances and adjustable bias voltages for accessories
US9351065B2 (en) Loudspeaker enclosure system having detachable wireless headphones and control method thereof
JP5633073B2 (en) Amplifier
JP5409430B2 (en) Gooseneck condenser microphone
CN104244141A (en) Earphone audio output control circuit
TW200723662A (en) Switching power-converting device capable of decreasing low frequency common-mode voltage at the secondary side
JP7212935B2 (en) headset
TW201838427A (en) Wiring structure of apparatus for converting audio signal to improve crosstalk and apparatus for converting audio signal
US20160192094A1 (en) Device for playing music and control method thereof
KR20150107518A (en) Electronic device having function for removing noise
CN104424938A (en) Double-row single-coil double-pickup unit
JP5067838B2 (en) Microphone power supply
US8306239B2 (en) Public-address system
TWI520512B (en) Network connection device and system
US20110209598A1 (en) Portable preamplifier for musical instruments
JP5017036B2 (en) Microphone power supply device and balance adjustment method thereof
JP4273019B2 (en) Condenser microphone
JP3225821U (en) Master clock generator that can switch GND potential of output signal
US11159865B1 (en) Media-source-integrated speaker and system for custom stereo installation
JP3154994U (en) Matching box for microphone
CN208158836U (en) Earphone extended line and earphone
TW202103500A (en) Separable speaker apparatus and operation method thereof
WO2006100911A1 (en) Portable apparatus with built-in fm transmitter
KR101640946B1 (en) Receiver device
TH15882C3 (en) Ultrasonic power supply, ultrasonic mosquito repellent

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20140203

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20140805

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20140807

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140908

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20140925

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20140925

R150 Certificate of patent or registration of utility model

Ref document number: 5633073

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees