[sdiy] Making an 8038 not suck

[scottnoanh at peoplepc.com]

Hi Aaron,

Thomas' trick was to operate the 8038 from a single supply, namely the
negative rail.  This vastly improves the IC's performance - operating it
from +V and -V makes the thing run hot.  Running it from +V involves having
to exceed the positive supply to get max range, so to simplify things even
more operate it from negative supply (use ground as +V and -15V as
'ground').  This makes controlling it much easier without having to resort
to standing on your head.

Cheers,
Scott



----- Original Message -----
From: "Aaron Lanterman" <lanterma at ece.gatech.edu>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, November 24, 2006 3:03 AM
Subject: [sdiy] Making an 8038 not suck


>
> Hi there,
>
> One of my students is interested in playing around with the ICL8038. I'd
> be interested in doing something useful since there is a ton of them
> sitting around in a random drawer in one of the labs that hasn't been
> touched in ages, probably.
>
> I know they have a limited sweep range, and inherently linear control, and
> have been generally declared to suck, but I still thought it would be a
> useful student exercise to see what they could coax out of it. Normally I
> would steer them elsewhere, but we have so many 8038s sitting around
> unused...
>
> Two quick questions:
>
> 1) I recalled Thomas Henry was able to decrease the amount of suck in the
> 8038 my some cleverness. His site, sadly, is long gone, but I found a
> discussion on the Wayback Machine:
>
>
http://web.archive.org/web/20031014162445/www.midwest-analog.com/diylvco.htm
l
>
> Sadly, the schematic is not achived. Does anyone have that?
>
> 2) The SDIY archives make reference to an electronotes article in which
> someone rigs a 8038 to use exponential control. I just went through my
> electronote collection up to around 1982 and couldn't find the article,
> but that is a LOT of electronotes to go through and a lot of the material
> is buried in weird ways (and the early electronotes don't have tables of
> contents), so I could easily have missed it.
>
> Anyone know what EN issue this is in, if it exists at all? Or even a
> ballpark guess of what year to look in?
>
> 3) Any other ideas for decreasing the suck in a 8038?
>
> - Aaron
>
> --------------------------------------------------------------------------
---
>
> Dr. Aaron Lanterman, Asst. Prof.
> and Demetrius T. Paris Junior Prof.    Voice:  404-385-2548
> College of Electrical and Comp. Eng.   Fax:    404-894-8363
> Georgia Institute of Technology        E-mail: lanterma at ece.gatech.edu
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