About VCF's

[Ullrich Peter]

>     Hi DIY'ers,
>     
>     I'd like to know if anybody on the list has ever built a 4-pole 
>     lowpass VCF using four identical 3080 OTA integrator stages, like the 
>     4-pole from the Electronotes ENS-73 series (right around issue #41).
>     
>     * How did it sound?
>     
>     * How did it handle distortion?
>     
>     * Are the individual offset trims on each OTA critical, or do you just
>       have to trim the overall offset?
>     
>     Also, how about the same filter type, except using better OTA's like 
>     the 13600 or 3280? Anything sound like an SSM2040?
>     
>     Sadly the SSM2040 is a scarce part. When I built one of those I was 
>     quite surprised at the warmth of it. I've been reading the thread on 
>     the "Secrets of the 2040", and I wonder if rather than trying to bias 
>     a CEM3320, if a discrete design has ever been found that sounds as 
>     good (except maybe an original Moog ladder).
>     
>     Also, I've sent an email to Analog Devices about the availability of 
>     the SSM 2044/2045/2047, no response yet. Their Designer's Reference 
>     databook says that these are not in normal production but are still 
>     available, and I've never tried them. Are they as wonderful as the 
>     2040?
>     
>     Thanks,
>     
>     - Gene
>     gstopp at fibermux.com

Hi !

Taday I got a datasheet from Analog Devices of the SSM2164. It is a low cost
quad VCA.

Features:
  4 high performance VCAs in single package (DIP 16 or SOIC 16)
  100dB dynamic range
  0.02% THD
  no ext. trimming
  120dB gain range
  0.07dB gain matching
  class A or AB operation

Sounds very interesting - sorry I don´t know the price...

Peter


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                    Ing. Peter Ullrich     mailto: ullrich at kapsch.co.at
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