Mick F wrote:.....From what I remember, the BB dynamo was just that .......... a dynamo ......... and produced DC. I was never able to strip it down to see or maintain the brushes.
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I had one (Soubitez BB gen) which was indeed reliable but was unfortunately unable to remove it when the bike frame was damaged but I can't see why they would make it a DC dynamo: surely unnecessarily complex compared to the usual claw-pole generator around which the Stzvo voltage curve is based... Some modern dynamos (lite spin / 12V axa spoke / sun-eco spoke) are not claw poles and use electronics to meet the Stvzo curve ).
CJ used to comment that the Stzo was based on slower German utility cyclists so speedy sporty UK persons could improve bulb life by fitting a pulley cap to bottles and/or fitting a inverse-series-zener clamp regulator like the Reflectalite presumably was.
I have just bought a Soubitez BB generator on ebay to (attempt to) make a maus-style top roller for my folder....