Although the SynthEdit environment is very easy to work with, I still spent quite a bit of time bouncing around the web looking for any help I could find at putting together simple audio circuits with the program. At the time no-one was building guitar amps with SE, and it was considered an inferior application suited for only creating midi/synth-esque modifiers.
On this page you will find downloads of the original working files to some of my plugins. I have not included all of them as most where based on a successful circuit release then salt was added to taste for a new version (along with frog's breath and worms wort to simulate reverb and aid in IR compatibility). You will need to supply your own GUI, will most likely need to have the third-party modules installed as used in some of the circuitry. Hopefully these are a useful head-start for the beginning amp modeler using SE. I do not warrant any of the files or provide support, tutorials, suggestions, so use at your own risk.
Edit Jan 2020: Couldn't find the original SE files off backup, but we're talking 10 years ago so anywhoo.