JPH0113456Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound effect amplification circuit incorporated in audio equipment, in which the functions of a graphic equalizer and a tone control are provided in one amplification circuit.

A graphic equalizer or tone control is each an independent audio amplifier, and in the past, it was expected that the price would increase significantly to provide these two functions.

An object of the present invention is to provide a sound effect amplification circuit that can have a graphic equalizer function and a tone control function by simply adding simple elements.

The present invention will be explained below with reference to embodiments shown in the drawings. The non-inverting input terminal of the amplifier A1 is connected to the input terminal IN via the resistor R1, and the inverting input terminal is connected to two or more inverting input terminals connected in parallel to each other (in the illustrated example, two or more
) is connected to the non-inverting terminal via variable resistors VR1 and VR2, and is connected to the output terminal via resistor R2.
Connected to OUT. Variable resistance VR1, VR2
The middle portions of are grounded via circuits 1 and 2, respectively, and between the sliders 3 and 4 and the ground, there are capacitors C1 and C3, interlocking switches S1 and S2, and resistors R5 and R5, respectively. R8 and semiconductor inductors L1 and L2 are provided. Semiconductor inductors L1 and L2 are connected to capacitors C2 and C, respectively.
4 and resistors R4 and R7, resistors R6 and R7, and operational amplifiers A2 and A3, and performs the same function as an inductance element.

In this circuit, if switch S1 is connected to the inductor L1 side, switch S2
is the connection position where resistor R8 is short-circuited, and as shown in Fig. 2, capacitor C1 and inductor L1 are inserted between slider 3 of variable resistor VR1 and ground, and the slider 4 of variable resistor VR2 and A circuit is formed in which a capacitor C3 and an inductor L2 are inserted between the ground and the ground. That is, as shown by the chain line in FIG. 4, a circuit is formed that functions as a graphic equalizer having a peak at a frequency determined by the capacitance and inductance of C1 and L1, and C3 and L2.

On the other hand, when the switch S1 is switched to the resistor R5 side, the switch S2 is switched to short-circuit the capacitor C3, and as shown in FIG.
Capacitor C1 between slider 3 of VR1 and ground
A circuit is formed in which a resistor R5 and a resistor R5 are inserted, and a resistor R8 and an inductor L2 are inserted between the slider 4 of the variable resistor VR2 and the ground. In this case, due to the action of capacitor C1 and resistor R5, a characteristic with a high response on the high frequency side is obtained, and due to the action of resistor R8 and inductor L2, a tone control with a high response on the low frequency side is obtained. The result is a circuit with characteristics as shown by the solid line.

As mentioned above, the sound effect amplification circuit of the present invention can realize the graphic equalizer function and the tone control function by switching the switch, and since it uses only one type of basic circuit, it is easy to use. The two desired functions can be obtained at low cost with a simple configuration. Furthermore, since the inductor is made of a semiconductor, it has the advantage of not being affected by magnetism such as hum, and of having a good space factor.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention;
3 and 3 are circuit diagrams realized by switching the circuit, and FIG. 4 is a circuit diagram realized by switching the circuit.
FIG. 2 is a characteristic diagram of the circuit shown in FIG. A1-A3...Amplifier, C1-C4...Capacitor, L1, L2...Semiconductor inductor, R1-
R8...Resistor, VR1, VR2...Variable resistor.

Claims (1)

[Scope of utility model registration request] an amplifier that non-inverts and amplifies an input signal; two variable resistors connected in parallel between a non-inverting input terminal and an inverting input terminal of the amplifier and whose intermediate portions are grounded;
a first switch for switching and connecting a series circuit of a first capacitor and a first semiconductor inductor or a series circuit of the capacitor and a first resistor between the slider of the one variable resistor and ground; In conjunction with the first switch, a series circuit of a second capacitor and a second semiconductor inductor or a series circuit of a second resistor and a second semiconductor inductor is connected between the slider of the other variable resistor and the ground. 1. A sound effect amplification circuit comprising a second switch for switching and connecting the circuit, and configured to have a graphic equalizer function or a tone control function by switching the switch.