intersil VCO chips and 'synth-level' circuits...

[Hairy Harry]

Hi Nick:

I'd avoid the 8038. People have tried and usually are not
satisfied. It does not have the linearity to be a good VCO.
There is a Harris / Intersil app note someting like
"Everything you ever (never) wanted to know about the 8038"
check it out.

I'd go with boosting the guitar/bass to synth level because you
can get the gain very quietly with a good preamp. Then at the output
you can attenuate to get back to line level.

I DO NOT agree that these circuits can be considered "low speed digital". 
They are high quality analog, or your synth will sound
awful. Very careful attention to layout is essential to getting
good performance.

H^) harry



>From: Nick Zuccaro <nmz77 at yahoo.com>
>To: synth-diy at node12b53.a2000.nl
>Subject: intersil VCO chips and 'synth-level' circuits...
>Date: Tue, 5 Dec 2000 08:30:25 -0800 (PST)
>
>
>has anybody here used the intersil icl8038 as a VCO? i stumbled
>upon it and it's looking like a pretty nice cheap-n-dirty
>soultion for chip-level modular units. newark has them for about
>$4/per, and they only need a few external resistors and opamps,
>depending on the application. the .pdf datasheet can be found
>here:
>
>http://www.intersil.com/data/FN/FN2/FN2864/FN2864.pdf
>
>just checking to see if anybody's used these, i'm planning on
>grabbing a few to see how they work out.
>
>
>another quick question, i'm relatively new to synth modules, i'm
>planning on integrating some modules with the rest of the gear
>i've got, which is at line level, mic level and guitar/bass
>level, so i'm assuming i'll need some kind of level 'adapter' in
>order to use all of these together. would it be better to use a
>synth level->line level converter to use everything at line
>level <studio standard> to take advantage of passive
>attenuation, or to convert the line level stuff i've got to
>synth level, which is +/- 2.5v? i'm trying to familiarize myself
>with working with synths, which i haven't really worked with
>before. seems like you can treat these circuits like low-speed
>digital, so most of the analog low-level design/layout rules
>aren't as critical. is this a correct assumption? anyway, just
>hoping to start some interesting discussion...l8r...Nick
>
>
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