Yeah - sorry for forgetting the diode cut - I'll correct the vero when I can today. Late night
. But it would have still worked with the diode shorted...
As for the 22uF cap, I flipped it on purpose because my LTSpice simulation indicated that the lower voltage was towards the junction of the resistors, but check it out in your working circuit and make sure the negative end of the cap is on the lower voltage side. For lower value caps (e.g. 1 uF) I often use film or non-polar electrolytics so I don't have to worry about that...
Let us know how it sounds. LTSpice says it should have a very flat response.