Using 741 is the least of your worries
What is this circuit supposed to do?
Each lowpass and highpass filter has adjustable gain upwards, but it doesn't go below unity. The two potmeters are effectively both just adding more gain to the entire bandpass signal (the filter curve will change a little bit as well), so why have two adjustments that do almost the same thing?
I assume you want to sum the three outputs. For a proper virtual earth mixer you need three separate 1k resistors -- not a single one. You have now shorted all opamp outputs together, so they will have to fight each other when the three signals are different at any point in time. See figure 4 in
http://sound.westhost.com/articles/audio-mixing.htm for a better solution.
It looks like the last opamp is there to invert the signal, but it won't work that way. Study the schematic. You have shorted the output directly to the output of the mixer opamp before it. An inverting amplifier with no gain needs two resistors of the same value. One into the negative input and one in the feedback loop.
If you intended it to work like a typical three band EQ with cut and boost, I would advise you to use the extremely common Baxandall style EQ, like figure 2 in
http://gilmore2.chem.northwestern.edu/projects/equal_prj.htm or this one
http://electroschematics.com/6201/3-band-equalizer/
Home
Help
Search
Login
Register
