Winfield Hill wrote:

Eeyore wrote...

In response to various posts please find attached a mic amp
which has seen volume production in commercial equipment.

Feel free to ask any questions / criticise whatever.

Graham

Content-Type: image/jpeg; "mic amp.jpg"

It's nice to see the diff-pair currents going directly to
the output opamp, with it's 6.8k resistors. But why'd ya
steal away loop gain so aggressively by choosing 680-ohms?

It doesn't. The + and - op-amp input nodes see almost no differential ac signal
voltage due to feedback action.

Hence no-need for active loading either. The 680Rs simply set the DC condition.

Graham