Doepfer

This used to happen on my ARP 2600 VCA and was a DC offset problem. 
Happily there was a straightforward calibration solution accessed 
with a small screwdriver through a tiny hole in the front panel and 
explained in detail in the manual.

I have a few of the old CEM based A-131 and a couple of RS-180 VCAs 
used with various different mixer/amp/ouput scenarios and never had a 
thump problem from these.

Sounds very much like a calibration issue - you really don't want to 
have to compromise your ADSR times or start filtering unnecessarily 
just to get a decent response from your VCA. Hopefully there's a 
simple solution.

Sean

>I believe this is solely due to your amp. I have experienced this
>with several devices, including RS180 (ASys), A132-1, A132-3, ASol
>SY01, and even the RS100 filter, if I just modify the amplitude (or
>cutoff frequency) with a gate or a fast envelope. Maybe it's just
>because you and I have cheap amplifiers, or maybe it's just inherent
>to the voltage levels of modular synths (and their rates of change).
>But I think slowing down the envelope time is the only cure.
>
>Anyone with a nice amplifier or monitor have an opinion?
>
>Monroe
>
>On Fri, Feb 20, 2009 at 10:34 PM, mirror_saw7778 
><<mailto:haven1%40gmail.com>haven1@gmail.com> wrote:
>>  I have a pair of 132-3 VCAs and love them except one thing which is
>>  making me sad. When I control them with a 143-2 ADSR they make a low
>>  "thump" sound. This sound happens regardless of input signal volume or
>>  frequency. the sound actually makes nice kicks ;) but makes a mess or
>>  my delayed arpeggio patches.
>>
>>  The VCAs are in exp mode. the only way I can make it go away is to use
>>  a slower attack on the ADSR. the only other VCA I have tried is a Asol
>>  SY02 which does not "thump". the SY02 is not DC coupled AFAIk.
>>
>>  I have the ADSR and the VCA's in separate G6 racks.
>>
>>  any suggestions? could this be DC offset due to ground issues? I do
>>  have a furman power conditioner on the AC.
>>
>>
>
>
>


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