For an update I'm just pasting in my posts from the Lister CS Power forum.
As with others, I have desired to reduce flicker with my st-5/6-1, and I never could get more than about 113 volts at full load. So I built the McCreary simple regulator discussed here and am posting the results with the hope someone may find it usefull. I've consulted with Bruce McCreary several times in the course of this project and he has been a great help with the success of it.
I used a project board from Radio Shack instead of the ExpressPCB board.
The pass transister Q1 used is IRGB14C40LPBF as the specified one is unavailable. I mounted it to a small heat sink I had on hand and it operates warm to the touch. I would use a bigger heat sink next time but I'm not worried about this one. The regulator is mounted in a box off the generator.
http://picasaweb.google.com/lh/photo/5-9KPEVOVPmdTIUr9N-ffA?authkey=Gv1sRgCN-YqvmH1oi44QE&feat=directlinkWhen first hooked up I found my inverter/charger would not accept the power and investigation with an oscilloscope showed some voltage spikes on the waveform. A 50 uf capacitor across the line fixed that problem.
The end result is less flicker than before, stiffer voltage regulation, and the ability to actually adjust my voltage up to 120 volts. The flicker is only noticable with incandecent bulbs and just slightly in a mercury yard light. Compact flourecents have none.
IMO this is a worthwhile project and for whatever reason can easily be reversed as the Z winding wires are just disconnected and taped off.
73, RH