4 lines Stereo Mixer

With this circuit you can mix four separate audio inputs. Each input will accept high or low impedance microphones, phonograph, tape or aux signals. You can adjust the gain of each input by adjusting each respective pot. With the Stereo/Mono switch you can combine just inputs 1,2 and 3,4 or in the Mono position combine all four inputs. More: Signal response is 20 Hz. to 20kHz. with very high input impedance and very low distortion with complete output short circuit protection. This circuit will drive any power amp with an input impedance of 2,000 ohms.

The circuit described functions as a four-channel audio mixer, capable of handling various audio sources such as microphones, phonographs, tape players, and auxiliary signals. Each of the four input channels is designed to accommodate both high and low impedance devices, ensuring versatility in audio source compatibility.

The gain for each input channel is adjustable via a potentiometer (pot), allowing for fine-tuning of audio levels before they are mixed together. This feature is crucial for achieving a balanced output, particularly when dealing with sources that have differing output levels.

A Stereo/Mono switch is incorporated into the design, enabling the user to select between stereo operation and mono mixing. In stereo mode, inputs 1 and 2 can be mixed separately from inputs 3 and 4, providing a dual-channel output suited for stereo applications. Conversely, when the switch is set to mono, all four inputs are combined into a single output, which is beneficial for applications that require a unified audio signal.

The circuit boasts a frequency response range of 20 Hz to 20 kHz, which covers the full spectrum of human hearing and ensures high fidelity in audio reproduction. The design includes a very high input impedance, which minimizes loading effects on the audio sources and preserves signal integrity. Additionally, the circuit is engineered to maintain very low distortion levels, contributing to clear and accurate audio mixing.

To enhance reliability, the circuit features complete output short circuit protection, safeguarding the mixer and connected components from damage due to unexpected faults. This protection is particularly important in live sound applications where equipment may be subject to various stresses.

Finally, the output stage of the mixer is capable of driving any power amplifier with an input impedance of 2,000 ohms, making it suitable for a wide range of audio amplification systems. This compatibility ensures that the mixer can seamlessly integrate into existing audio setups without the need for additional matching devices.With this circuit you can mix four separate audio inputs. Each input will accept high or low impedance microphones, phonograph, tape or aux signals. You can adjust the gain of each input by adjusting each respective pot. With the Stereo/Mono switch you can combine just inputs 1,2 and 3,4 or in the Mono position combine all four inputs. Signal response is 20 Hz. to 20kHz. with very high input impedance and very low distortion with complete output short circuit protection. This circuit will drive any power amp with an input impedance of 2,000 ohms. 🔗 External reference