Betreff: RE: [sdiy] Re: 4049 and 4069

[jhaible at debitel.net]

Does this this mean very old ones are too noisy
because of bad material, and modern ones are
too noisy becaus eof shrinked transistor
size, and there is an optimal period from 
where to get "vintage CMOS" ?

Didn't understand the noise vs. hum part, btw.

JH.



> And the year of production is interesting, too.
> 
> Surface problems and gate oxide integrity
> have improved considerably since 1970 or so.
> 
> Perhaps, modern stock CMOS is not useable for noise
> because of bad S/N (noise voltage too low compared to hum
> etc...).
> 
> m.c.
> 
> > -----Original Message-----
> > From: jhaible at debitel.net [mailto:jhaible at debitel.net]
> > Sent: Dienstag, 20. Januar 2004 13:20
> > To: Czech Martin
> > Cc: synth-diy at dropmix.xs4all.nl
> > Subject: RE: Betreff: RE: [sdiy] Re: 4049 and 4069
> > 
> > 
> > > > Are _all_ MOSFETs so bad, noise-wise?
> > > 
> > > No, the noise corner can be controlled by gate oxide quality and
> > > surface quality within some limits. 
> > 
> > 
> > Then it would be interesting to see which brand of 4069
> > has the "lowest" noise, compared to others, at least.
> > 
> > Alot of manufacturers make (or used to make) 4069s.
> > Has anybody compared them, noise-wise?
> > 
> > JH.
> > 
> > -------------------------------------------------
> > debitel.net Webmail
> > 
> 
> 




-------------------------------------------------
debitel.net Webmail