Hi. I'm building a mic pre-amp, and require a split rail from a single rail 12v supply. So I'm using a typical op-amp virtual ground circuit, with a TL071 and a couple small BJT's. My pre-amp circuit will only draw about 20mA standard, worst case <100mA if the output is shorted.
I get a nice clean +5v / -5v with reference to the virtual ground... except the current consumption is huge! The shown circuit is drawing about 100mA with no load. Adding a load makes the current increase as expected (ie; add 10mA load makes the total current consumption 110mA). Needless to say the transistors and regulator are cookin'! Any idea why so much current? We did find one error on the PCB, but have corrected that and installed all new components, and still this big current draw.
I modelled this in LTSpice, and I get nowhere near this sort of current. Hummm....
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Would much appreciate any suggestions, insight or education anyone can provide. Thank you in advance!
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EDIT: Added PCB layout. Q3 collector and emitter are backwards, we have bodged this on PCB for now.