Volume Controller Circuit: Complete Guide on How to Build one

The course helps to build an audio device. A volume control circuit is a wiring system found in a volume controller.

Significantly, adjusting the volume assists in finding the correct volume and balance level for our audio equipment.

We will discuss the volume controller circuit, its working, and the step-by-step process of making one.

Also, it will help you learn and make the right connections for your needs!  

1. What is a volume controller?

Volume control is a balance controller. This controller has an interface with push buttons for external control in a TSSOP package.

Notably, a volume controller does not require an external circuit.

Because the device has an inbuilt bias voltage source, reducing the number of external components.

A single or dual power supply can operate a volume controller integrated IC.

(volume knobs)

2. How Does Volume Control Work?

Volume control efficiently works with a certain phenomenon.

This phenomenon is that the volume reduces any time you rotate the volume knob to the left.

On the other hand, turning the knob to the right increases the volume.

However, the factors behind the phenomenon are pretty complicated.

The control knob acts as a variable resistor in an electrical circuit.

When you turn the resistor in a specific direction, the knob is a resistor.

In that, it raises or reduces the resistance from electrical signals.

For example, you reduce the resistance when turning the knob to the right.

Thus allowing more volts to travel to the speaker raising the volume.

Contrastingly, turning the knob to the left increases the resistance.

This action reduces the volts that can reach the speaker, reducing the speaker's volume.

Notably, the process becomes complex when you involve an amplifier.

But, overall, the audio control involves the number of volts reaching the speaker.  

(a sound amplifier.)

Circuit description

(A volume control circuit diagram)

Channel inputs and outputs

Pin 8 receives the right channel input, while pin 17 gets the left channel input.

The right and left channel inputs go in separate directions. It is because the right input goes to the high terminal.

The left input should reach a high terminal of the second internal digital preset potentiometer.

But, on the first internal digital potentiometer of the IC.

Notably, Pin 6 and 9 are the low terminals of the inexpensive internal potentiometers.

These pins become short after they join pin 11 using connecting wires.

Also, Pin 11 is the mid-bias voltage output of the IC.

Pin 10 contains the right channel output.

Pin10 is the buffered wiper terminal of the first internal preset potentiometer.

At the same time, the second internal inexpensive potentiometer contains the left channel output.

The presence of a capacitor at pin 12(bias generator bypass) to the ground is a must.

Pin 12 helps to prevent noise biasing. Significantly, bypassing noise from the VLOGIC and VDD sources improves the complete performance and stability of the circuit.

Additionally, capacitors C3 and C4 carry out the noise biasing process.

(control knob regulator)

LEDs and resistors

D5 and D1 are indicator LEDs. The LEDs indicate balance and volume levels.

Resistors R5 and R1 limit current via status indicator LEDs. Contrastingly, resistor R6 activates the LEDs by showing the volume.

When there is a center position, the LED at the center glows.

This action only occurs if the electronic circuit is in balance control.

However, the LEDs stay off when the system is in mute performance.  

Push Buttons

S1, S2, S3, and S4 in the circuit are push buttons. Push-buttons S1 and S4 work to control the circuit.

When you press S1, you will be pushing the circuit into mute mode.

But, when you push S4, you will be selecting between audio balance control mode or volume control mode.

Also, LED D6 will indicate which mode you push.

On the other hand, pushing the S2 and S3 buttons will increase and decrease the volume.

It is only when the circuit is in volume control mode.

Additionally, these two buttons can shift the balance to the right or left when the system is in balanced mode.

Connecting the VSS pin to the ground is essential.

After grounding the shutdown pin, IC will enter shutdown mode automatically. Pin 6 is the shutdown pin.

Notably, Pin 6 joins the VLOGIC source to achieve its shutdown function.  

(a black volume control knob)

3. How to Build a Volume Control Circuit?

Importantly, the following steps will guide you in making a proper volume controller.  

Step 1: Creating the circuit design.

In our case, we will use BNCs as the principal input/output connectors.

However, you will add a few stereo jacks for convenience.  

Step 2: The hardware equipment required.

For the project actuation, you will need the following parts.

• One dpdt switch.
• One chunky metal acts as the volume knob.
• Two stereo jacks measuring 3,5mm each.
• One audio taper potentiometer.
• One aluminum enclosure.
• 2 BNC connectors.
• An audio wire, hookup wires, soldering tools, and workshop tools.

Since there are different types of potentiometers, select the right one.

Therefore, check out the potentiometer's resistance, the taper, and sometimes the manufacturer.

Additionally, the variable resistor should have high resistance, and the taper should be a logarithmic taper resistor for audio applications.  

(key volume knobs)

Step 3: Prepare the enclosure.

Importantly, ensure you measure every hole in the enclosure the jack will go through.  

Step 4: Dry fit.

First, try to fit your components in the drilled holes. Always ensure you leave enough room for wires.

Finally, ensure the volume knob and potentiometer fit on the box.  

Step 6: Spray it.

Since we used an aluminum box, you can spray the box with the color of your choice.

However, this step is optional.  

Step 7: Wiring system.

Importantly, connect the input signal and the output signal to the precision potentiometers.

This step ensures the rotation of the knob to change the volume.  

Step 8. Assembling

Assemble all parts and close the box up.  

Step 9. Could you test it out?

Your controller is now ready to use. Therefore, connect it to your music and test the electronic circuit.  

(vector volume knob sets)

Summary

We’ve given this article information on what the volume controller circuit does and how they work.

If you want to learn more about your circuit-related projects, contact us!

Our team is always happy to answer any questions from you.