Is this useful for audio? The claim is that this design has bandwidth independent of the input current: http://www.google.com/patents?id=sxgIAAAAEBAJ&dq=6323723
The type of current mirror I've usually used is this one: http://upload.wikimedia.org/wikipedia/en/2/24/Imp_wilson_cs.gif
The type of current mirror I've usually used is this one: http://upload.wikimedia.org/wikipedia/en/2/24/Imp_wilson_cs.gif