Control two Op-Amps with one volume

[ata90]

Assume circuit below:



How can we implement a circuit with equivalent performance in which we can change both of resistance of potentiometers with only one volume? in the other word, we have just one potentiometer but we need to change gain of both Op-Amps identical (for example for two AC input signals, both Op-Amp amplify 10x that is control with one volume).

 

[poorchava]

The simplest sulution is to use stereo potentiometer. It's a kind in which there are essentially two separate potentiometers connected to common shaft in commom enclosure.

Other option is to use digital potentiometers. Look at AD, Microchip, Intersil, Maxim-Dallas. Then u just use an ordinary potentiometer hooked up to a small MCU which drives the digital pots.

Any other options are far more complex. Generally you can google for "variable gain amplifier". Those are pretty complex circuits to build from discrete components, but there are some IC's available. Like **broken link removed** or **broken link removed**. They are pretty high bandwidth for an audio application, but will do the job