Doepfer

thank you those who replied re the greasy filter question.
i read about the diode filter at the Doep website.  i'm unclear 
about what effects diodes have on the sound and the q.

what does it sound like?  why is it not as easy to self resonate as 
a different filter?
____________________________________t

--- In Doepfer_a100@yahoogroups.com, "primatetom2003" 
<baltimorescience@h...> wrote:
> thank you those who replied re the greasy filter question.
> i read about the diode filter at the Doep website.  i'm unclear 
> about what effects diodes have on the sound and the q.
> 
> what does it sound like?  why is it not as easy to self resonate as 
> a different filter?
> ____________________________________t


it is not difficult to drive a diode filter into self oscillation.
when turning up the resonance on a a102, you will get that
self oscillation very early (around 9 o'clock position).
the problem is that the resonance changes, when you sweep the
cutoff frequency and vice versa. the two parameters are not 100%
independent. diode tolerances lead to some strange behaviour,
the resonance varies in loudness and maybe will disappear at some
point, when you change the cutoff frequency. this is a bit
different on each a102. thats why it is difficult to use a
self oscillating a102 as a sine oscillator. also the overall
loudness changes when you turn up the resonance, so you have to
re-adjust the input attenuator too. but besides this, the diode
filter sounds cool. i would describe it as a bit "untamed" :-)