obsolescence (was Re: [sdiy] "Curtis" filter in Prophet 8)

[Tom Wiltshire]

IMO only if it's designed to fail shortly.

The DX7 (for example) includes a few Yamaha custom chips which have  
been discussed here before. Although they'd be impossible to replace,  
there's still a good number of DX7s still running after 20+ years.  
That's hardly obsolescence.
Likewise with any modern synth that uses custom parts.

This is a different thing to choosing a part that is deliberately  
under-specified, knowing that it will then cause the unit to fail  
around 6 minutes after the warranty runs out...

T.


On 23 Jul 2009, at 09:45, Graham Atkins wrote:

> David,
>
> Don't they call that "built in obsolescence" ?
>
> Graham
>
> On 23 Jul 2009, at 07:02, David Ingebretsen wrote:
>
>> Kind of figured that.
>>
>> But, it kind of makes me want the Prophet a bit more knowing it is  
>> a unique
>> beast.
>>
>> I'll have to check the piggy bank under the bed...
>>
>> Thanks Paul.
>>
>> David
>>
>> David M. Ingebretsen M.S., M.E.
>> Collision Forensics & Engineering, Inc.
>> 2469 East Fort Union Blvd. STE 114
>> Salt Lake City, UT 84121
>> www.CFandE.com
>>
>> 801 733-5458 Office
>> 801 842-5451 Cell
>>
>> dingebre at CFandE.com
>> dingebre at 3dphysics.net
>>
>>
>>
>>
>> ~~ -----Original Message-----
>> ~~ From: Paul Schreiber [mailto:synth1 at airmail.net]
>> ~~ Sent: Wednesday, July 22, 2009 11:31 PM
>> ~~ To: David Ingebretsen; synth-diy at dropmix.xs4all.nl
>> ~~ Subject: Re: [sdiy] "Curtis" filter in Prophet 8
>> ~~
>> ~~ They were custom for Dave only. Try calling there and ask.
>> ~~
>> ~~ Paul S.
>> ~~
>> ~~ ----- Original Message -----
>> ~~ From: "David Ingebretsen" <dingebre at 3dphysics.net>
>> ~~ To: <synth-diy at dropmix.xs4all.nl>
>> ~~ Sent: Thursday, July 23, 2009 12:12 AM
>> ~~ Subject: RE: [sdiy] "Curtis" filter in Prophet 8
>> ~~
>> ~~
>> ~~ > Well, then I guess my follow-up question would be can regular  
>> people
>> buy
>> ~~ > small quantities of these chips somewhere? Or, would it have  
>> been a
>> ~~ > special
>> ~~ > run for Dave Smith only?
>> ~~ >
>> ~~ > 1. It might be fun to experiment with the chips for SDIY.
>> ~~ > 2. I'm thinking of buying a Prophet 8 and the paranoid in me  
>> would want
>> ~~ > some
>> ~~ > spares should the unit fry.
>> ~~ >
>> ~~ > David
>> ~~ >
>> ~~ >
>> ~~ > David M. Ingebretsen M.S., M.E.
>> ~~ > Collision Forensics & Engineering, Inc.
>> ~~ > 2469 East Fort Union Blvd. STE 114
>> ~~ > Salt Lake City, UT 84121
>> ~~ > www.CFandE.com
>> ~~ >
>> ~~ > 801 733-5458 Office
>> ~~ > 801 842-5451 Cell
>> ~~ >
>> ~~ > dingebre at CFandE.com
>> ~~ > dingebre at 3dphysics.net
>> ~~ >
>> ~~ >
>> ~~ >
>> ~~ > ~~ -----Original Message-----
>> ~~ > ~~ From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>> ~~ > ~~ bounces at dropmix.xs4all.nl] On Behalf Of JJB
>> ~~ > ~~ Sent: Wednesday, July 22, 2009 6:09 PM
>> ~~ > ~~ To: synth-diy at dropmix.xs4all.nl
>> ~~ > ~~ Subject: Re: [sdiy] "Curtis" filter in Prophet 8
>> ~~ > ~~
>> ~~ > ~~ On the Dave Smith website he mentions somewhere that the  
>> Curtis
>> chips
>> ~~ > ~~ used in the Mopho are not New Old Stock, but an actual new  
>> run of
>> ~~ > Curtis
>> ~~ > ~~ chips. Now how does one go about making _that_ happen?
>> ~~ > ~~
>> ~~ > ~~  - Joel
>> ~~ > ~~
>> ~~ > ~~ Antti Huovilainen wrote:
>> ~~ > ~~ > On Wed, 22 Jul 2009, David Ingebretsen wrote:
>> ~~ > ~~ >
>> ~~ > ~~ >> While not strictly DIY, I am curious if anyone knows  
>> anything
>> about
>> ~~ > the
>> ~~ > ~~ >> Curtis low pass filter in the Dave Smith Prophet 8  
>> synthesizer?
>> Is
>> ~~ > it
>> ~~ > ~~ >> using
>> ~~ > ~~ >> Curtis chips or did they re-do the circuit with discrete
>> components?
>> ~~ > ~~ >
>> ~~ > ~~ > My guess is CEM3396, which is basically two half DCos,  
>> VC mixer,
>> ~~ > ~~ > CEM337x/338x style filter (similar to OTA even if  
>> internally
>> ~~ > ~~ > implemented with some shortcuts) and a final VCA.
>> ~~ > ~~ >
>> ~~ > ~~ > Antti
>> ~~ > ~~ >
>> ~~ > ~~ > "No boom today. Boom tomorrow. There's always a boom  
>> tomorrow"
>> ~~ > ~~ >   -- Lt. Cmdr. Ivanova
>> ~~ > ~~ > _______________________________________________
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>> ~~ > ~~ >
>> ~~ > ~~ >
>> ~~ > ~~
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