The Cyndustries List

Mark Barton suggested adding this...

The reason for AC coupling is simple.  When  a modulation signal is applied 
to the linear input, the frequency is supposed to modulate symmetrically about 
the center (note).  If there is any DC on the modulation signal, the note will 
"pull" to one side or the other, (depending on the polarity of the DC) as the 
modulation signal is applied.  You will hear this as a detuning or chirp of the 
tone if there is an envelope gating the modulation.  For these reasons, we 
carefully null the modulation VCA (multiplier) for any residual DC and we use 
a capacitor on the input to block any DC from entering from the horrible, 
corrupted outside world.

The beauty of linear modulation at audio rates is that the note stays put and 
only the timbre changes, if everything is done right.  This is not possible with 
exponential modulation because it is an inherently non-linear process. 

Thanks Mark!