emitter follower biased by input signal?

Question

For the standard emitter follower you typically need input coupling capacitors and a DC bias of roughly half the supply voltage however what if the input signal itself swings around half the supply voltage?

e.g if the previous stage to an emitter follower is a standard op amp non-inverting amp with a split supply (+12V,-12V) with the input referenced to centre point but the succeeding emitter follower is referenced to -12V (i.e +24V, 0V), so The op amp output is referenced to ''+12v'' relative to the emitter follower? Could this replace the input coupling cap and resistor biasing or would it not work?

Load would be a pair of headphones (50 to 300 ohm)

example of circuit is attached below

Differential emitter follower?

Inverting amp?

Answer 1

Could this replace the input coupling cap and resistor biasing or would it not work?

A more convenient idea would be this: -

It's called a DC coupled amplifier and uses feedback directly from the emitter to set the gain at the output to be: -

$$1 + \dfrac{R2}{R1}$$

Of course, if you really want the return current for your headphones to go via -12 volts (potentially noisier) then you will need an output capacitor.

Answer 2

If you mean ...

^{simulate this circuit – Schematic created using CircuitLab}

then with suitable op-amp biassing so that its output swings somewhere between the rails, the emitter follower will 'follow' the output at about 0.7 V lower.