[sdiy] cheap twin oscillators?

[Lee Mulvogue]

G'day

Just wondering if someone can point me in the right direction for schems to 
a simple, cheap twin oscillator?
I want to make a circuit to give me a "power hum" sound (like a 
high-voltage transformer), and I was thinking maybe twin oscillators 
slightly out of phase?  Do you think square waves with a very crude 
low-pass filter to round them off a bit would do the trick?
As I said, cheap and simple are the keys here, so I'm thinking maybe a dual 
IC of some sort?  Any help would be greatly appreciated.

Thanks
Lee
lee at baudalign.com