10 Feb 2011. AndrewT pointed out something really dumb I had done (in a most polite way) in the original circuit. The caps in the filter section are in series and effectively halved in value. The circuit will behave much better simply by deleting half the caps. I've uploaded the latest version of the file. Sorry to the 125 people who have already downloaded, and I hope I didn't cause too much head scratching as to why I had done that, I'm not even sure myself, and I'm surprised I never realised. I'm going to revamp this blog entry as there are some things I have realised since I first posted, but that will be over the next couple of weeks. Hopefully I will finally build it soon.

I have been spending an inordinate amount of time using LTSpice lately. The more I use it the more I like it! For someone like me who is somewhat challenged mathematically, and who's electronics theory knowledge level is well below where it should be (to be doing this sort of design anyway),...