Hi,
the circuit I've been having trouble with is a VCO (voltage controlled oscillator). It contains three op amp: a DC signal mixer, an amp (non-inverting) and a comparator. I wonder if I need a separate split power supply for each? The functional prototype works (it's a kludge) but this circuit will be manufacutred and I want to avoid any glitches. Also, are there any benefits of using a TLE2426 for virtual ground?