I'm with you LJ, up to a point! The old regulators were and can still be pretty good. I have several lying around, and they can indeed be tweaked to deliver. But I do have to say that their management of the field input leaves something to be desired, and the cut-out side is also sometimes prone to trouble. The reason I like the DVR2 is mainly this: it is not so wired that the residual magnetism of the dynamo has to produce, from a standing start, enough oomph to get transistors to operate (or if it is so wired, it gets over the problem I'll describe in a second). It also cuts out very fast - there is no discharge at tickover, at all - and cuts in as soon as it can contribute. Most mechanical regulators at v low rpm burden the battery, and the cut-in can be somewhat later than ideal. As I understand it, and I am absolutely no expert (barely understand what electricity is, to be honest), you need to produce at least 0.7v from a dynamo to get a transistor to perform whatever its role in life is. A lot of electronic regulators have used a pair of transistors coupled together - a 'Darlington Pair' - this means the residual or 'remanent' magnetism of the dynamo has to be enough to generate 1.4 volts from the armature before there can be any battery input to the field coil- which often means the said electronic thingummy won't cut in until you have given the engine more revs than are good for it from cold. Or it won't cut in at all.
However, I would never denigrate a decently maintained Lucas CVC box - amazing they work at all, let alone for so long, when you think how often the points on the regulator are opening and closing to average out the current getting to the field. And the fact that I keep the old ones says something! (You never know when you're going to need something, anything at all that works, on a dark and wet night . . .) Groily
