Doepfer

--- In Doepfer_a100@yahoogroups.com, "selfoscillate" 
<synaptic_music@y...> wrote:

in vca mode there is always a bit of a signal feedthrough,
which is not noticable in the other two modes.
afaik this is because of the characteristics of the
vactrols and a known side-effect. no problem imho,
it's the sound that counts. now i understand why the
buchla lowpass gate has such a good reputation.
i need to buy another one soon.
 
Interestingly enough, while the 291 lowpass gate does have bleed, it does 
only in the other two modes, not the VCA mode.  Regardless, Self speaks the 
truth here.  It's a quality of vatrols, the photo resistor being the cuplrit - they 
don't close down all the way, never will.

I would be interested to know the amount of bleed though.  The 291 is fine 
when used with Buchla signal levels (basically they are line outputs), but with 
Deopfer/Blacet/everybody else's in the six volt range, there's about 3mv.  I've 
been able to get this down to about a 1/4 of mv by throughing in a bit of 
feedback in internally.  It does effect the amount of ringing (which you want in 
a LGP), but you can easily pre-select your vactrols so that's not a problem.

Diet:  with your  res pot, you've got something close a lowpass Borg filter.  

- Peter