Integrating two oscillator schematics.

[Blunderland]

I've built the following square wave 555 oscillator circuit:

http://www.scottmetoyer.com/archives/simple-555-synth

I now want to integrate the following saw-tooth wave schematic to create a polyphonic synth:


http://www.electronic-circuits-diagrams ... ages/2.gif

Should I create the separate saw-tooth circuit then simply send it to the same output as the square wave?

Also do I need to use a separate 9v or is there anyway I can use the same one?

I also want to add an on/off switch for the synth, but if they are two separate circuits but just sent to the same output will I need two separate switches?

Any help would be hugely appreciated.