LM13600 vs LM13700N

[Edu Silva]

De: tomg <vco at mindspring.com>
 
> I haven't tried subbing one for the other in the vco designs,
> however I don't see any reason why not. I think you could build it out of
> 3080s and fet followers in a pinch. I did swap 700s for 600s in the mouse
> while I was compiling the parts list checking vcf and vca functions and
saw
> no difference at all. I'll swap them out later in a vco and see for sure.
I
> would bet it's ok.
> -tg

In the 13600, the bias current of the OTA is reflected into the output
buffer. It causes a DC offset at the output of the darlington and CV
bleedthrough that usually brings problems to VCA's: "thumps" when CV
changes suddenly.

Due to the darlington's low input Z, the VCO's suffers from limited range,
but it seems to work well with VCF's.

In the 13700, that connection doesn't exists, making it better for VCA's,
but don't know about filters and oscillators.

Have you tried the NE5517? Works good in audio applications, and maybe
worth trying it out in synths. I've never seen it in music circuits,
however. They're almost the same chip, but the difference is in the
connection between the OTA and the output darlingtons. A good field for
research, I think.

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil