# convert circuit from single to dual supply

Discussion in 'General Electronics Chat' started by yardcat, Apr 24, 2009.

1. ### yardcat Thread Starter New Member

Nov 27, 2008
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I am very curious as to the how of converting a battery powered elec guitar effect to using a dual supply. The circuit, which I have attached, runs on a 9 volt battery. The supply is divided, +9v, +4.5v, and gnd. If I am using +9v,0v, and -9v, what do I need to do to adapt the circuit?

There is a lot of information on converting to a single supply and none that I could find in converting to a dual supply. Any help would be appreciated. I am sure you can tell, my grasp of electrical engineering is weak. Thanks, yardcat

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2. ### mik3 Senior Member

Feb 4, 2008
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Use only the +9V and ground wires, power the 9V lines directly (if the power supply is regulated) and use a voltage regulator (like LM317) to regulate the 9V to 4.5V.

Mar 24, 2008
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4. ### SgtWookie Expert

Jul 17, 2007
22,183
1,728
The "quick" conversion would be to wire two 9v batteries in series (one +/red lead to one -/black lead).

Remove the portion of the circuit that's dividing the single 9v supply to 4.5v.

Connect the common connection between the two batteries to what was the +4.5v supply, which will now be 0v/ground.

Connect the + (red) lead of the two batteries to what was the +9v supply.

Connect the - (black) lead of the two batteries to what was the ground, which will now be -9v.

This doesn't address the shield connections; they would now be connected to -9v instead of the new 0v/ground. You're probably using 1/4" mono phono plugs/jacks. Those would need to be rewired.

C9 should be replaced with a non-polarized capacitor.