[sdiy] VCF Questions

[Magnus Danielson]

From: bill berzinskas <housenationmedia at yahoo.com>
Subject: [sdiy] VCF Questions
Date: Sun, 29 Dec 2002 19:35:23 -0800 (PST)

> Hey everyone..   

Hi Bill!

> hope you all had a lovely holiday..  santa was good to me and brought a
> little money, which of course went to the synth.. 

Good for ya'!

> i'm looking thru VCF schematics trying to find one that i feel comfortable
> building, but still with a good sound..   i've run across rene schmitz's
> schematics..

Check out the ASM-1 VCF schematic, which BTW quite close to the Oberheim SEM
VCF which might also be an option (you've got many lovely 741s right there
next to the CA3080s).

>  i see alot of references to nF on the caps..  this is going to sound dumb,
> but how do i convert that to pF or uF?  I don't really have access to nF
> cap's at this time..

Sure you do. n (nano) is a fine SI prefix which seems to have a hard time on
the North-American continent. Anyway, 1000 nF = 1 uF 1000 pF = 1nF, so...

1 T<unit>  = 1 * 10^12  <unit> (Tera-prefix)
1 G<unit>  = 1 * 10^9   <unit> (Giga-prefix)
1 M<unit>  = 1 * 10^6   <unit> (Mega-prefix)
1 k<unit>  = 1 * 10^3   <unit> (kilo-prefix)
1  <unit>  = 1          <unit>
1 m<unit>  = 1 * 10^-3  <unit> (mili-prefix)
1 u<unit>  = 1 * 10^-6  <unit> (micro-prefix, really a small greek micro)
1 n<unit>  = 1 * 10^-9  <unit> (nano-prefix)
1 p<unit>  = 1 * 10^-12 <unit> (pico-prefix)
1 f<unit>  = 1 * 10^-15 <unit> (femto-prefix)
1 a<unit>  = 1 * 10^-18 <unit> (atto-prefix)

Under normal circomstances, that should be all you need... (actually, those
where the onces I recalled straight out) however, since I'm not quite as
normal (and now I cheat a little...), I also give you:

1 Y<unit>  = 1 * 10^24  <unit> (Yotta-prefix)
1 Z<unit>  = 1 * 10^21  <unit> (Zetta-prefix)
1 E<unit>  = 1 * 10^18  <unit> (Exa-prefix)
1 P<unit>  = 1 * 10^15  <unit> (Peta-prefix)
1 h<unit>  = 1 * 10^2   <unit> (hecto-prefix)
1 da<unit> = 1 * 10     <unit> (deka-prefix)
1 d<unit>  = 1 * 10^-1  <unit> (deci-prefix)
1 c<unit>  = 1 * 10^-2  <unit> (centi-prefix)
1 z<unit>  = 1 * 10^-21 <unit> (zepto-prefix)
1 y<unit>  = 1 * 10^-24 <unit> (yocto-prefix)

where <unit> is being replaced by your favorite unit for the moment, like that
of

A for ampere (unit for electric current)
V for volt (unit for electric potential)
W for watt (unit for power)
J for joule (unit for energy)
Hz for hertz (unit for frequency)
C for coulomb (unit for electrostatic charge)
H for henry (unit for electromagnetic inductance)
F for farad (unit for electrostatic capacitance)
[greek ohmega] for ohm (unit for electric resistance)
N for newton (unit for force)
B for bel (unit for log10 relation in powers)
g for gram (unit for mass well, the actual SI unit is kilogram, but anyway)
s for second (unit for time)

If you want to learn more on units, check out NIST Special Publication 330
which is a download away from getting in your hands. Beware however that this
is non-normative, on certain aspects even missleading to the unexperienced
reader.

Sorry for the rambling, but this stuff is seems to kreep up every now and then.

>   also, if anyone has any good schematics revolving around the 3080, could you please send them? :-)   any other input would be great too..

Both the ASM-1 VCF and the Oberheim SEM VCF is CA 3080 based, so that should
fit you nicely.

Cheers,
Magnus