Glide circuit of the ProphetV

[Roel Das]

I've got a little trouble figuring out this circuit. (I don't have any
experience doing this...)

My guess:
The Iabc input of the 3280 limits the current provided to the output? (Or is
it the opposite?)
And because this is the current provided to (un)load the capacitor, it
controls the glide...
The voltage follower buffers the capacitor.

But what is the use of the diodes?
And the transistors? I suppose buffering?
And, when you use the 13700, you don't need the buffer, because you can use
the one on the chip right?

And the last question, R3121 4,7K in the feedback loop. Is it needed, or is
it just additional gain?
Thanks,
Roel

----- Oorspronkelijk bericht -----
Van: "Harry Bissell" <harrybissell at prodigy.net>
> You got it.... The circuit works real well, you could also use a CA3080,
or
> LM13600 or 13700 here... I's use the more available 13700 since the
darlington
> buffer isn't needed.
>