There are two basic reasons why audio tone circuits are used. The first reason is to regulate the signal’s BANDWIDTH when it enters the audio POWER amplifier. If the bandwidth is not constrained, it may be impossible to recover the original signal at the speaker. The second reason is that the music makes me happy. Controlling the frequency of the signal to be amplified by the audio power amplifier is known as Audio tone control. A mixed frequency audio signal is the most common type of audio signal. BASS refers to low frequencies in audio transmissions, while TREBLE refers to higher frequencies. When it comes to separating the frequencies in an audio stream, an audio tone circuit comes to mind.
Audio tone control circuits can be divided into two categories. The active tone control circuit is the first, while the passive tone control circuit is the second. If an amplifier is present in an audio tone circuit, it is considered to be active. When there is no amplifier, the circuit is referred to as a passive tone control circuit.
This article explains you how to design an audio tone circuit with the gain of around 25. This design needs less number of components and it is cost effective.
- Audio Tone Control Circuit Diagram:
- Audio Tone Circuit Design:
- Amplifier Stage:
- Tone Control Circuit:
- Dual Power Supply Circuit Design:
- How to Operate Audio Tone Circuit:
- Audio Tone Circuit Advantages:
- Audio Tone Circuit Applications:
- Audio Tone Circuit Limitations:
- Audio Tone Circuit Design:
Audio Tone Control Circuit Diagram:
Circuit Components:
- TL072 Operational amplifier
- 100k Pot – 3
- Audio jack
- Resistors – 2.2M, 100k(2), 10k(2), 1k(2),
- Capacitors – 100pF, 1uF, 2.2uF, 22nF(2), 220nF, 2.2nF
Audio Tone Control Circuit Design:
The audio tone circuit mainly consists of two sections – one is amplifier and other is passive tone control circuit.
Amplifier Stage:
The TL072 non inverting amplifier is used in the amplifier stage. To provide feedback to the operational amplifier, resistor R3 is placed between pins 1 and 2. Through the resistor R4, pin 2 of the op amp is linked to the ground. The gain of the operational amplifier is set using resistors R3 and R4. In non-inverting mode, the gain of an operational amplifier is given as
Av = 1+ (R3/R4) (R3/R4) (R3/R4) (R3/R4) (R3/R
The first stage’s input impedance is about equivalent to R3. The C2 capacitor is utilised as a decoupling capacitor as well as a low frequency cutoff capacitor. The offset impact on the operational amplifier output is reduced by resistor R2. This resistor’s value should be nearly equivalent to R3||R2.
Tone Control Circuit:
The tone control portion has a 20dB boost capability. Pot RV1 controls the BASS in this area, while the other pot controls the TREBLE. The VOLUME is controlled by Pot RV2, while the BALANCE is adjusted by Pot RV3. The separation between BASS and TREBLE is provided by resistor R7.
Dual Power Supply Circuit Design:
Circuit Components:
- 12-0-12V, 500mA center tapped transformer
- Diode bridge – 1A
- 680uF Electrolytic capacitors – 2
- 0.01uF capacitors – 2
The audio tone circuit receives electricity from this circuit at +15V and -15V. The voltage is stepped down using a centre tapped transformer. Four 1n4007 diodes make up Diode Bridge D1. This diode bridge is used to convert AC electricity into pulsing DC. The AC ripples are filtered using capacitors.
How to Operate Audio Tone Control Circuit:
- Connect the wires according to the circuit schematic.
- Make sure there is a common connection between the AC and DC while making the connections.
- From the Dual power supply circuit, supply +15V and -15V to the audio tone circuit.
- With the help of the audio jack, connect the audio input to the circuit.
- By adjusting the BASS or TREBLE, you can change the audio tone.
- You can alter the loudness by using the RV2 pot.
Audio Tone Control Circuit Advantages:
- The circuit uses less components and it is cost effective.
- The circuit is portable.
Audio Tone Control Circuit Applications:
- This audio tone control circuit is used in Audio systems to control the audio tone.
- Used in music players to control the bandwidth.
Audio Tone Control Circuit Limitations:
- This circuit is simulated in software and may require some changes in practical.
