[sdiy] Reply-to: music.maker at gte.net

[Scott Gravenhorst]

Hi Dave,

Personally, I find no difference in the sound between these two.
Both produce slightly imperfect saws, differently, but perhaps
the difference is in harmonics so high I don't hear them.  The
imperfections exist mainly around reset.  Both designs are much
more than capable of 2 or 3 octaves (I got 7 out of my 4069 with
a linear V-I converter instead of expo).

I would use the René Schmitz 4069 design, primarily because in one
14 pin IC package, (plus 3 transistors) René packed an expo VCO
with PWM.  The 7555 would require an extra IC package or more 
transistors to get PWM.  Both designs require a bipolar supply
AFAIK.

Dave Magnuson <resfreq at hoohahrecords.com> wrote:
>Hi List,
>
>After playing with my SH-101 for a while, my 7 year old daughter decided
>she wants a monosynth.  Err, umm, actually, after playing my SH-101, I
>decided I WANT IT BACK, so I'm building her a monosynth to keep her
>occupied so I can go steal it!

Taking candy from a baby... (c:

>I have enough left over circuits here to build almost the entire project
>already (LFOs, EGs, VCFs, VCAs).  The only thing I'm lacking is a VCO.  I'd
>like to keep this VERY simple, and scalability isn't too important (I can
>build a better VCO later if it ever becomes an issue).  I'd like maybe 2 or
>3 octaves of range, so I'm thinking of trying the 7555 or 4069 based VCOs
>that we've been discussing lately. 
>
>What are people's opinions of the SOUND of these two oscillators?  I know
>Scott G has heard both for sure... anyone else want to say which design
>they think *sounds* better?  I'd prefer to build the VCO with the most
>"character".  I know this is a very subjective matter, but...
>
>Thanks!!!
>
>Dave Magnuson
>
>Resonant Frequency:
>resfreq at hoohahrecords.com
>http://www.hoohahrecords.com/resfreq/index.html

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