AW: LM13700 vs. CA3080

[Haible_Juergen#Tel2743]

>Is there any difference between 1/2 of an LM13700 (not counting the buffer)
>and
>a CA3080?  Is the decision to use one or the other just based on whether 
you
>need one or two and whether or not you can use the buffers?

This is a good question !
I used to think they are identical (and used the 13700 everywhere), but I
am not sure anymore.
The 13700 is "improoved" "3080-type", if I remember the data sheet 
correctly.
And indeed, the gm value is the same as for the 3080 (unlike the 3280,
btw). But *maybe* they changed something in the current mirrors which
might cause slight differences in sound. This is not prooved, however.
I just won't claim that they are identical anymore.

> Also, if you you're not using the buffer in a LM13700, is it a good idea 
to
> ground the input or anything?

It can't hurt, but is not necessary IMO. As long as you don't connect 
anything
to the emitters (Pin 8 and 9) no current can folw thru the darlingtons, 
anyway.
This would be different for the 13600, where the 1st stage of the darlington 
is
loaded by a current source internally.

JH.