AW: EG design

[Haible Juergen]

	>Is there any point charging an envelope generators timing cap
with a
	>constant current source, variable of course, to generate a
linear change in
	>output pd. Or do exponential rises and falls sound more
realistic. mmm,
	>there's a thing, realism, I'm not sure thats the right word. My
D-50 (shock
	>horror) seems to have linear EGs, at least the diagrams on the
front
	>suggest that, and they sound very odd on a slow attack/decay
setting.

	>Any one built a analogue linear EG?

You got it: linear ramps are kind of unrealistic. They have their use,
but exponential ones are more "natural".

It's far more easy to build voltage controlled linear ramps than
exponential
ones. The Synthi A shows how easy it is. Or ask Gene Stopp about 
his experiments with opto isolators.
And existing ota-based exponential ramp circuits can easily be changed
to linear ones by altering the feedback resistors, so that the ota
inputs
are overloaded.

JH.