[sdiy] UAF42

[phillip m gallo]

Yes using Vactrols obviates the cap matching;  

It's the min parts/small footprint SVF that was interesting re:Vactrols
and this chip (and was why i acquired two of these way back when).  

Of course, with time spec creep demanded that i take advantage of the
cap match and once envisioned with OTA's etc the space reduction is lost
and so these chips sit in a box unused.  Now if you use a SSM2164 in
combination the small footprint does return somewhat.

regards,
p

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of René Schmitz
Sent: Tuesday, February 24, 2004 1:32 PM
To: Scott Stites
Cc: music.maker at gte.net; synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] UAF42


Hi Scott^2 and List,

> Good points, indeed.  I have to agree with Phillip, though, for 
> Vactrol hounds like me, it would make a pretty compact little SVF 
> (haven't calculated it yet, but I think the 1000 pF caps in that case 
> would be fine).  Of course, the matching of the Vactrols would 
> obliterate the spec on the caps =-D.

My thoughts exactly! The integrators aren't the weakest link anyway, I 
even think the SVF is so popular because it is not very critical with 
regard to matching of the timing capacitances. So wether you use an 
UAF42 or just some decent styrene caps and a decent quad opamp, is IMHO 
just a matter of taste.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159