[sdiy] UAF42

[Scott Gravenhorst]

Wow.  Digikey's search response is ambiguous.  It shows both hits for
stock and hits for obsolete material.

http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=238492&Site=US&Cat=31589264

Still, it's a chunk of change, even if at $7.50 each.

<philgallo at attglobal.net> wrote:
>Well according to TI it's still in production in DIP and SMD but now
>that  Burr Brown is TI, the old fab is obsolete.  You can find it's
>product page @:
>
>http://focus.ti.com/docs/prod/folders/print/uaf42.html#inventory
>
>The appnotes and the design software can be found there.  
>
>The budgetary for 1k pcs is $7.55 US so the old Digikey markup rears
>it's head again.    These chips conform to the standard "pricey" Burr
>Brown marketing model.
>
>Being that an SVF needs only two precision caps, a Mouser order for
>poly's and a little handpicking is probably a better solution.  
>
>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 2:53 PM
>To: synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] UAF42
>
>
>I thought for a fixed cutoff filter bank, "why not?" until I did a
>search.  I checked Jameco, Digikey and Mouser, only Digikey 
>had it (around 1000 in stock) for $12.58 in unit quantities, no larger
>quantity prices were listed.  Digikey notes that it is 
>obsolete.  For _that_ much $, I think a  decent quad opamp and 
>some good caps might be more economical.
>
>
>
>Scott Stites <scottnoanh at peoplepc.com> wrote:
>>Hi Scott,
>>
>>Good points, indeed. I have to agree with Phillip, though, for
>>Vactrol hounds like me, it would make a pretty compact little SVF 
>>(haven't calculated it yet, but I think the 1000 pF caps in that 
>>case would be fine). Of course, the matching of the Vactrols 
>>would obliterate the spec on the caps =-D. 
>>
>>An exponential current sink to drive the Vactrols would take a
>>couple of transistors, and, while I'm at it, hang a Vactrol off 
>>of pin 3 and get VC resonance. 
>>
>>Now that Rene Schmitz 4007 design......I'll definitely have to try 
>>that, too!
>>
>>Cheers,
>>Scott
>>
>>-----Original Message-----
>>From: Scott Gravenhorst <music.maker at gte.net>
>>Sent: Feb 24, 2004 12:37 PM
>>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
>>>
>>>
>>
>>=========================================================
>>- Where merit is not rewarded, excellence fades.
>>- Hydrogen is pointless without solar.
>>- What good are laws that only lawyers understand?
>>- The media's credibility should always be questioned.
>>- The only good terrorist is a dead terrorist.
>>- Governments do nothing well, save collect taxes.
>>
>>-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>>-- Linux Rex         | RedWebMail by RedStarWare
>>-- FatMan: home1.gte.net/res0658s/FatMan/
>>-- NonFatMan: home1.gte.net/res0658s/electronics/
>>-- Autodidactic Master of Arcane and Hidden Knowledge.
>>
>>
>>
>>PeoplePC Online
>>A better way to Internet
>>http://www.peoplepc.com
>>
>
>=========================================================  
>- Where merit is not rewarded, excellence fades.
>- Hydrogen is pointless without solar.
>- What good are laws that only lawyers understand?
>- The media's credibility should always be questioned.
>- The only good terrorist is a dead terrorist.
>- Governments do nothing well, save collect taxes.
>
>-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>-- Linux Rex         | RedWebMail by RedStarWare
>-- FatMan: home1.gte.net/res0658s/FatMan/
>-- NonFatMan: home1.gte.net/res0658s/electronics/
>-- Autodidactic Master of Arcane and Hidden Knowledge.
>
>

=========================================================  
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- The only good terrorist is a dead terrorist.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/FatMan/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Autodidactic Master of Arcane and Hidden Knowledge.