I was looking for a way to drive some VU meters kindly given to me by fdlsys. I was going to just copy the circuit of the Scott amp it came from, but realised i couldn't use it because that amp has a split supply, so I wouldn't have the midpoint ground reference. I found all sorts of ideas, mostly using op amps. But then I found this - A simple passive logarithmic VU-meter. It works similarly to the Scott circuit but just needs input and ground. I'll probably have to fiddle a bit with the resistor values because my meter is 1200 ohm. (interestingly it is so sensitive that the tiny current the multimeter uses for measuring deflects the needle almost to 0dB). I thought may be useful to share in case others have VU/Power meters lying around.
Pretty straightforward:
Pretty straightforward: