Building an waveshaper device for my analog synth
simulate this circuit &ndash; Schematic created using CircuitLab
The attached circuit will allow you to vary AC phase shift from 0 to 170 degrees.
you would have to experiment and test it, as I'm not sure what affect the distortion caused by such a circuit would have on the audio effect your after.
Hope this is some help.
It's good to see someone doing some homework before asking the forums!
Ben.