Mixer preamplifier with tone control

A general-purpose preamplifier/mixer accepts up to four inputs, has a gain of 1600, and provides bass and treble controls that can be varied ± 10 dB at 100 Hz and 10 kHz respectively. More: IC1 and IC2 = LM301A.

This circuit design features a versatile preamplifier/mixer capable of handling up to four audio inputs, making it suitable for various audio applications. The gain of the preamplifier is set at a high level of 1600, which ensures that even low-level signals can be amplified effectively for further processing or mixing.

The circuit utilizes two LM301A operational amplifiers (IC1 and IC2), which are known for their high-speed performance and low noise characteristics. These op-amps are configured to provide the necessary amplification and mixing functions. The input stage can accommodate multiple audio sources, allowing users to blend different signals seamlessly.

To enhance user control over the audio output, the circuit includes bass and treble equalization features. The bass control adjusts frequencies around 100 Hz, while the treble control affects frequencies near 10 kHz. Both controls offer a variable adjustment range of ± 10 dB, enabling users to fine-tune the audio output according to their preferences or specific acoustic environments.

The preamplifier/mixer is designed to provide a balanced output, ensuring compatibility with a wide range of audio equipment. This circuit is ideal for applications in home audio systems, recording studios, and live sound setups, where flexibility and sound quality are paramount. Proper power supply decoupling and grounding techniques should be employed to minimize noise and ensure optimal performance of the LM301A op-amps.General purpose preamplifier/mixer accepts up to four inputs, has a gain of 1600, and provides bass and treble controls that can be varied ± 10 dB at 100 Hz and 10 kHz respectively ICI and IC2 = LM301A,.