[sdiy] Cool chip alert

[phillip m gallo]

Perhaps some folks haven't seen this UAF42 application.

http://www.uwm.edu/People/msw/AudioOsc/Panels.html

regards,
p


-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Scott
Gravenhorst
Sent: Tuesday, February 24, 2004 9:37 AM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Cool chip alert


Wow, I thought it was a wanked design as well.

The other URLs pointing to clever usage of this were OK, but I think
there's something seriously wrong with using external OTAs to allow
voltage control of something like this.  The integrators on the chip
should have been made of OTAs, not opamps, IMHO.  That would have been
far more useful than what they did.  After all, a SVF - VOLTAGE
CONTROLLED, can be made out of a single dual OTA IC.  And if I want to
mess with unusual designs, I'll happily build the René Schmitz 4007 VC
state variable filter.  I fail to see anything superior about this IC
other than the matched 1000pf caps (which are too large IMHO and you're
stuck with them).  And I think that there are ways we can match caps to
make a better OTA based VC-SVF.

Just my $.02 worth of pure opinion.











Colin Hinz <asfi at eol.ca> wrote:
>On Mon, 23 Feb 2004, Tim Escobedo wrote:
>
>> http://www.speakjet.com
>>
>> Might be useful for sone nice effects.
>
>Who are these people? And why did they let such a wanker design their 
>website?
>
>Okay, I don't really expect an answer to the second question, though 
>neither of their news items display anything except the headline. Oh 
>well, I'm sure they've got a very good reason for doing it this way.
>
>The company's main website is much closer to being wank-free, luckily:
>
>http://www.magnevation.com/
>
>I do wonder what's in the guts of the SpeakJet -- it's not like a few 
>guys working in an industrial park in Alabama can suddenly build a fab 
>to start churning out mixed-signal ASICs..........and as they're really

>clear about providing an entirely American-made product (and I don't 
>have any problem with "buy domestic" campaigns, as we could use a bit 
>of that up here), so that implies a fab in the USA.
>
>Looks like quite an interesting chip. If I thought there'd be any 
>chance I'd get around to doing something with them in my lifetime, I'd 
>buy a few. But first I'd better build something permanent with my pair 
>of SN76477s......
>
>- Colin Hinz
>  Toronto, Canada
>
>

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