[sdiy] Wallwarts and ground?

[James R. Coplin]

So, I’m helping a friend finish up his MFOS Sound Lab project and I want to run it off of a 9v wall wart instead of batteries.  The power supply delivers +/-9v but no dedicated ground.  I guess I never thought about it as I always just use the power supply for my modular so voltage and ground paths are always there.  What do I do to provide a ground with the wallwart supply?

James R. Coplin