I'm working on a DIY analog synth based on the CEM3340 chip. When feeding it 12V at VCC it will output waves at different amplitudes that I'll want to scale to 5V to -5V:
Square: 0-10.7V
Sawtooth: 0-8V
Triangle: 0-4V
To scale those waves to -5V - 5V I'm using a differential op-amp config with the values calculated here as seen above:
My question is: using that calculator, I need to keep VRef relatively low, around 2.5V otherwise I start to get negative values for resistors. In my circuit, I have a 10V ref voltage that I would like to use as VRef. Is it possible to change the op-amp config to divide my 10V voltage ref to 2.5V? I've tried to use a voltage divider before R15/R17/R19 but failed. I would also like to keep the config non-inverting. Is something like this possible with only one op-amp unit?
Thank you!