JPS5816320Y2 - Magnifying sound image device - Google Patents

Description

[Detailed description of the invention] This invention relates to an audio circuit using an expanded sound image circuit, and the operation is most improved when combined with an earphone circuit.
The purpose of this invention is to provide a device with low power consumption in an audio circuit system.

FIG. 1 shows an enlarged sound image circuit, and this circuit will be explained below.

The audio signal applied to the terminal 1 is applied to the audio output amplifier circuit 2 and amplified, and further amplified by a class B push-pull amplifier circuit consisting of transistors 3a and 3b. connected to one end.

The other ends of the speakers 5 and 6 are connected to both ends of the secondary winding of the transformer 7.

The middle point of this secondary winding is grounded.

The audio signal at the input terminal 1 is applied to a delay circuit 9 via a capacitor 8 to be delayed, further amplified by an amplifier 10, and applied to the primary winding of the transformer I.

The phase of this delayed and amplified audio signal is reversed by 180 degrees by a transformer 7, and the main audio signal and speakers 5, 6 are output.
are synthesized and emitted.

It has been confirmed that the sound image enlargement effect is best when the delay time of the delay circuit 9 is about 5 m5ec.

When combining this circuit with an earphone circuit, if the conventional means 1.1 is introduced, the main audio signal will not come out from the speaker when the earphone is used, but the delayed sub-audio signal will come out from the speaker, which is still inconvenient.

Therefore, the present invention aims to prevent neither the main audio signal nor the delayed sub-audio signal from coming out of the speaker when using earphones, and also to eliminate wasteful power consumption in the audio circuit system. Explain using.

FIG. 2 shows an embodiment of the present invention, and the same parts as those in FIG. 1 are given the same numbers and their explanation will be omitted.

Connect the output side terminal of the capacitor 4 to 1 of the earphone transformer 11.
It is connected to a contact 13a that is connected to the next winding and also contacts one terminal 12a of the earphone circuit 12.

One end of the secondary winding of the earphone transformer 11 has a high resistance 13
The earphone circuit 12 is further connected to one terminal 12a of the earphone circuit 12.

The other end of the secondary winding of the earphone transformer 11 is connected to the other terminal 12blC of the earphone circuit 12.

One terminal of the earphone circuit 12 is further connected to one end of the speakers 5 and 6.

One end of the primary winding of the transformer 7 is connected to a contact 13b that contacts one terminal of the earphone circuit 12, and the DC power terminal 14 is connected to one terminal of the earphone circuit 12.

This connection may be reversed. When the earphone circuit 12 is not used, the circuit state is as shown in FIG. is also in the operating state, and the sub audio signal is also output from speaker 5,
Join 6.

Next, when a jack is inserted into the earphone circuit 12 and the earphone is used, an audio signal obtained at the secondary winding of the transformer 11 is applied to the earphone.

At this time, the contacts 13a and 13b are connected to the earphone circuit 12.
Since the main audio signal is separated from one terminal of the speaker 5,
It will not go to 6.

At the same time, since no DC power supply voltage is applied to the amplifier 10, there is no sub-audio signal from the amplifier 10, and there is no sub-audio signal sent to the speakers 5.6.

In this way, when the earphones are used, no signals are applied to the speakers 5 and 6, and the operation of the amplifier 10 is stopped, so unnecessary power consumption can be eliminated.

As a means to prevent the sub-audio signal from being applied to the speakers 5 and 6, the amplifier 10 is configured as a class B amplifier, and the amplifier 1
0 through the primary winding of the transformer 70, and connect the contact 13b in series with the input path of the amplifier 10.
A switch circuit using one terminal 12a of the earphone circuit 12 may be connected to the earphone circuit 12.

In this case, when the switch circuit is turned off, the audio signal no longer enters the amplifier 10, so naturally the input signals from the speakers 5 and 6 also disappear.

In the case of the class B amplifier 10, power consumption decreases when there is no input signal, so unnecessary power consumption can be reduced.

As described above, according to the present invention, when an earphone circuit is added to a device that magnifies a sound image and emits sound from a speaker, it is possible to prevent both the main sound and the sub-sound from being added to the speaker when using the earphones. Since the power consumption of an amplifier for amplifying audio can be eliminated or reduced, unnecessary power consumption is reduced, which is also economically advantageous.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an enlarged sound image device, and FIG. 2 is a circuit diagram of an enlarged sound image device according to an embodiment of the present invention. 1...Audio input terminal, 2, 3a, 3b, 10.
...Amplifier, 11...Earphone transformer, 13a. 13b... Contact, 12... Earphone circuit, 12a, 12b... Terminal, 5, 6-
...-Speaker, 7...Transformer, 14...
...DC power supply terminal, 9...Delay circuit.

Claims (1)

[Scope of utility model registration request] A first amplifier that amplifies the audio signal, the output of the first amplifier is connected to a contact that contacts one terminal of the earphone circuit, and is also connected to a primary winding of the earphone transformer, and a secondary winding of the earphone transformer. Connect one end of the wire to the above one terminal of the earphone circuit, connect the other end of the secondary m of the earphone transformer to the other terminal of the earphone circuit,
One terminal of the earphone circuit is connected to one terminal of each of a pair of speakers, the audio signal on the input side of the first amplifier is applied to a second amplifier via a delay circuit, and the output of this amplifier is phase-shifted. In addition to the primary winding of the diverted transformer, ground the middle point of the secondary winding of this transformer, connect both terminals to the other terminals of the pair of speakers, and contact the one terminal of the earphone circuit. An enlarged sound image device comprising another contact, and a switch circuit constituted by the contact and the one terminal connected in series to the signal input path of the second amplifier or the power supply circuit.