[sdiy] NE5517

[harrybissell]

I did some initial testing with the NE5517 and 5517A in a simple
filter circuit (a modified EFM VCF1e).   This is a very simple SVF
based on the app note for the LM13600 / LM13700

initial findings

The NE5517 is a viable sub for the LM13600

I founf a weird effect.  At very low Iabc (when the filter sections
should be
cut off)... the DC level of the filter drifts down substantially. With
the LM13600
the sound is cut off totally, but with the NE5517 there is a null point,
when the
Iabc goes lower, there is MORE signal feedthrough... perhaps some
capacitive
effect ???

Output drift with Iabc is about equal for LM13600 and NE5517, the A
suffix is a little
better.  Sound wise I think they are about equal as well.

I'll get into some more formal tests when I make a better fixture....

H^) harry