Trying to build a symmetrical power supply from a VDC input without the problems of virtual ground
The 'standard' virtual ground circuit is one of these. The split voltage does not drift with any current drawn, and the degree of split is programmable with choice of resistor values. Try these first, and only complicate them if you need to.







simulate this circuit &ndash; Schematic created using CircuitLab

Most cheap op-amps will handle 10mA or more output current, and there are versions with higher output currents. The circuit on the left is adequate for many applications. 

With a buffered output, the circuit on the right will typically take you to 1A with single output transistors, and 10A with darlingtons.

The right hand circuit is suitable for many applications, but it would exhibit cross-over distortion if the polarity of the unbalance current changes. 

A simple improvement is a single resistor of 100ohms (700mV/7mA) between the output transistor bases and emitters (200ohms for darlingtons). This allows a small output current to be provided by the amplifier directly, which mitigates much of the crossover behaviour, while reducing the maximum output current available slightly.

Both circuits can be upset by driving into a heavy capacitive load, which will often be the case when supplying a split rail device that has a large electrolytic on each rail. The standard resistor/capacitor arrangement shown below can be tuned to stabilise most situations.







simulate this circuit