Hey guys,

I'm studying the Korg Monotron schematic in my quest to get a general idea of how synthesizers may be designed.

I have a particular question about the schematic. In the bottom left corner is the power module. Unless I'm missing something, the only source of voltage for the entire system is the two AAA batteries which is 3 volts. But if you look, they have the VCC rails labeled as +5V. Where is the additional voltage gain coming from?

 

Hello,

Did you see IC 1 next to the battery?
This chip acts as a boost regulator to create the 5 Volts.

TI has some details on the chip:
http://www.ti.com/product/tps61071

Bertus

 

But I thought you couldn't just "generate" energy. Their boost regulator is connected to the same source.

 

Sorry for the double post, but another question is how are they powering their opamps with just a single rail?

 

Hello,

IC2B is used to create the "BIAS"signal, wich functions like a virtual ground.
All over the schematic you will see little triagular symbols that will be connected to this "BIAS" point.

Bertus

 

But I thought you couldn't just "generate" energy. Their boost regulator is connected to the same source.

You are absolutely correct. When you step up the voltage, the available current is reduced and, so, the amount of power (energy) is the same -- minus the losses in the conversion. These losses are typically 10 to 20 %.