combining circuits and power rails

[isher1992]

Kind of a newb question...but.

I was getting the itch to try and put something together, and wanted to build either a Marshall Guv'nor clone or some other overdrive, and add ROG's "Tonemender" to it in place of the passive tonestack.  My knowledge of electronics is fairly limited; I know the basics, but when it comes to adding this circuit to that (as far as active circuits go) I'm somewhat confused.

The power rails are different for both circuits on their own, so how would I go about altering those to combine the two circuits together?

[slacker]

Think about what happens if you run two pedals in series both powered from the same power supply by a daisy chain or separate leads. The grounds from both pedals get connected together both by the shield of the audio lead and by the fact that the grounds on the DC jacks are connected together at the power supply or in the lead of a daisy chain. The same thing happens with the +9 Volts for both pedals, they are connected either at the power supply or in the daisy chain.
So the simple answer is you connect the grounds together and connect the positive rails together. You might be able to do more, for example both the tone mender and the Govnor use a voltage divider to generate 4.5 volts or vref, as both circuits have this instead of building that part twice you could use one voltage divider and connect all the vref points to it.

[isher1992]

I was wondering if it was that simple.  I noticed they were both 4.5 Vref, but the values being different on the voltage divider threw me off.

[slacker]

R.G has a nice article about bias circuits and resistor values http://www.geofex.com/circuits/Biasnet.htm

[GibsonGM]

If you tie, say, "board 1" and "board 2" together, it might be wise to put a 10uF cap across + and - where the power enters the second board, just for decoupling.   Probably overkill, but hey - it shows we're thinking about such things, he he!