I'm working on an interface that will be connected instead of a speaker, input of my interface is differential, and output is single ended.
I'm using the following schematics :
R3 is the load to simulate the speaker, the R1/R7/R4 group is here to decrease the level.
I would like to easily adjust the gain by acting on R2 (knowing that I should act the same on R5) but I need a major value change to see a minor change on the output, I'm using Proteus to do the simulation.
Do you see an alternative to my scheme? or can I use a transformer to move from differential to single ended then use an AOP to adjust the gain?
Best Answer
You can use variable gain amplifier like this one, that you can connect either to a potentiometer, or to a DAC, it will come much cheaper than a digipot and solve lots of the issues related to it to the design.
There are plenty of those, controlable from an analog source, or digital like I2C, SPI...