[sdiy] Matrix12 CEM3372 trick and CEM3396 question

[Rainer Buchty]

On Tue, 2 Oct 2007, jbv wrote:

> but 1 question remains : what could I do with the "wasted" vca on the 
> 3396 ? any smart suggestion ?

You could use it as a "fattener" to add the LP-filtered signal to 
whatever your outside circuit computes by just summing up that generated 
signal with CEM's VCA output.

> actually what happens to the regular vcf output that feeds the vca 
> when applying the matrix12 trick to the vcf cells ?

To my understanding it should still work as a 4-pole LPF, as all you do 
is tapping the individual filter stages. (As you also can see from the 
Xpander schematics, the LPF's output is still used as the feedback path, 
i.e. fed into RESin.)

Rainer


P.S.: How would the resonance behavior change, btw, if not the LPF's 
output but the generated signal (i.e. VCAin in the XPander example) 
would be used as feedback? Or, in other words, would it be musically 
sensible, or is it better to stay with the phase delay given by the LPF?