Banana jacks and impedance

[Grant Richter]

> 
> Damn, why on earth isn't _everything_ +- 10v p-p?
> 

Because it radiates like a Bitch! This is a good reason to
use shielded patch cables. Even then there's enough signal
to capacitively couple from an input to an output jack with power
removed entirely from the module.

Here's a test - if you think you have bleedthru in your VCA,
try removing power from the VCA and see how much signal
still comes though just from capacitve coupling.

One of the problems of banana cord systems is to get the 
signals from muted patches to go away. If you have
a very loud TB-303ish bass screaming in one channel and a
high-hat with mostly silence in another, even with the bass
muted you can hear it in the high hats. Just a matter of
capacitive coupling of crossing wires.

In "theory" the low output impedance of the op-amp should
absorb the signal - but the low output impedance is a function
of the op-amp servo mechanism, which becomes less
effective as frequency increases.