Power supply plus minus ground hmph

[The Magic Rabbit]

Is there any reason I couldn't take a 12VDC power supply, use a 5VDC regulator to give me 12VDC, 5VDC, Gnd, and treat it as if it were +7VDC, Gnd, -5VDC?

If this is the case, why would you then use a single rail OP Amp and bias the input to it, since you have to then filter the DC at in and out?

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[jeroen79]

Depends on what you are using it for.
If the load between +7V and GND is passing more current than the load between GND and -5V the regulator will have to be able to sink current.
If it can't then it's voltage will rise above what it is trying to maintain and it will just stop passing current, leaving you with the two loads in series on a 12V supply.
You could of course add another load between GND and -5V that is drawing enough current to always keep the regulator sourcing current.

[The Magic Rabbit]

Depends on what you are using it for...

I was hoping to build an 8 channel pre-amp that will connect to my computer audio interface inputs (unbalanced line level at 20k impedance) and take a variety of things as inputs (mics without phantom power, synthesiser, line output from amplifiers, etc)

I want to drive a set of 8 LM358NG OP Amp chips, plus possibly a set of 8 YL071CN Op Amps with standard 3mm LEDs as overload indicators.

My main thinking was that all these capacitors and biasing seems to add a lot of components that might simply be unnecessary.

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