Nigel (and gang),
Please forgive me if I'm straying off topic here...
I was just looking at your Analogue Board Tutorial... Very nicely done Sir, as are all of your tutorials that I've stumbled upon this past year...
Admittedly, I don't know a great deal about op-amps, but may I ask if this circuit could be simplified using 'single-rail' op-amps? Might this eliminate the need for a negative voltage rail...
Thank you again for your time and kind consideration...
Regards, Mike