[sdiy] Tau Systems

[Dave Manley]

I'd assume any design decisions for Japanese transistor radios were driven solely by cost.  Were PNPs cheaper to fab in the early days?

Dave (how many parts can we stand on end and shove in this little plastic box?) Manley

 On Wed 11/03/30  9:57 AM , "Harry Bissell" harrybissell at wowway.com sent:
> I've never heard that PNP transistors are less noisy than NPN. Why are they
> less noisy ?
> (is that why almost all 60's Japanese transistor radios preferred PNP
> ?)
> H^) harry
> 
> 
> ----- Original Message -----
> From: rtarcan <rtarc
> an at superonline.com>To: s
> ynth-diy at dropmix.xs4all.nlSent: Wed, 30 Mar 2011 12:17:57 -0400 (EDT)
> Subject: Re: [sdiy] Tau Systems
> 
> On 30.03.2011 10:30, lante
> rma at ece.gatech.edu wrote:> I know Juergen Haible did a lot of work with the
> Tau Pipe phaser, but the only other reference to Tau Systems I've been able
> to find is on Jim Patchell's website:>
> > http://www.oldcrows.net/%7Epatchell/TAU1010/tau.html
> >
> > And speaking of transistor ladder VCFs using
> PNPs, the Tau 1010 is one!>
> > The Tau 1005 is a triangle VCF (OTA-comparator
> type), and the 1050 looks like a sawtooth VCO (I think).>
> > Anyway, I was curious if anyone was familiar
> with the company? My google fu is failing at finding more information...
> most hits that come up involve either Juergen's version of the Tau phaser
> or a line of unrelated softsynths by Muon.>
> PNP transistors are less noisy then NPN's. This may be the reason.
> 
> 
> > I'm also casually curious if there are more
> PNP-based transistor VCFs out there, and for that matter, why one would
> choose to use PNPs instead of the more common NPNs in that
> topology?>
> > - Aaron
> >
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