Right, first up, here's a page on that there Internet. It's a nice page because it means an idiot like me can avoid having to understand too much, and simply go to the leccy shop with a nice readymade list of transdinglers and thruppits to weld together at my leisure:
http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm
For the moment, let's refer to the first and simplest circuit, enigmatically named "Circuit 1". This circuit is essentially the bit that sits between a dynohub and an LED to make one of them light up, hopefully the latter. Happy days.
Now, my first question is: Can I simply yank the diode out of that diagram and replace it with a single-LED head unit taken from any of the myriad lights (Magicshine etc) that are available? (ie are those head units free from other interesting stuff that will mean having to change the rectifier bridge?)
Second question, if the answer to the first is yes: does it then follow that the other modifications in that page are unaffected? (mainly interested in the smoothing and tuning capacitors in circuits 2 and 6)
Third question: how is all of this affected if I were to use a multi-LED head unit? (given that the hub is a constant-current source whereas the head units are designed for use with cells, ie constant voltage, I assume they would wire the diodes in parallel and if I wanted multiple LEDs I'd need to build my own circuit with the diodes in series)
If the answer to the first question was no, anyone got any pointers to info on how complex it would be to do any necessary modifications or build my own head unit from readily available parts?
Essentially I want to use this as a switched main beam in conjunction with a proper dip beam (which I already have), so the requirements are ~600lm of light in a symmetrical beam and no standlight - a combination for which there is (AFAIK) no out-of-the-box dynamo-ready unit (possibly the KTronic K-Lite, but that's the only possibility I've found).
