searchable archive (was Re: [sdiy] Chatterbox)

[R. Drake]

is there an web-based (searchable) archive for this list?  i'm relatively
new; the welcome message i got has instructions for retrieving
indexes/messages from majordomo via email, but no mention of anything
else...

the mention of previous discussion of the chatterbox spurred my curiosity,
but i wasn't sure how to find the old thread.


thanx,
luigi


on 1/30/03 2:55 PM, MED at teenagewasteland at prodigy.net wrote:

> Hello all,
> I'm seriously considering building the Chatterbox (discussed a while ago
> on this list). I'm ready to begin part aquisition mode. However, i have
> a question. The chatterbox uses 4000 series CMOS -- readily available
> stuff. It looks like a bunch of logic gates, a 4016 and a 4006 shift
> register for whitenoise. The switches are all touchswitches, controlled
> by skin resistance. These go directly to the input of a 4049 hex
> inverter/buffer.
> My questions are:
> isn't it extremely easy to damage 4000-series CMOS through static
> discharge, and wouldn't this arrangement lead to blown chips? (it's an
> extremely dry winter around here...)
> Which (if any) of the CMOS should be buffered(B) vs. unbuffered (UB)?
> What voltage does this circuit expect? I'm assuming +5 and 0.
> What opamp should i use to replace the ol' 741s they use?
> I'm leaning toward a few TL071. Would that cause problems? It looks like
> three of the opamps are just used to combine signals. However, in the
> formant filter area, there's four of them and I'm not sure how the
> attributes of other opamps would change the filter properties.
> What joystick should be used? Looks like double-ganged 10k pots in
> both directions.
> 
> -MED (Boy, i'm just FULL of questions today... must be 'cause I'm sick
> and procrastinating on a paper)