[sdiy] Need one of two things....

[Pete Hartman]

Thanks Neil!

Currently trying to absorb it.... :)

Pete

On Fri, Oct 30, 2020 at 7:52 PM Neil Johnson <neil.johnson71 at gmail.com>
wrote:

> Hi Pete,
>
> TI's AN-72 is a pretty good read on how Norton op-amps work and many
> applications, including all the "standard" circuit blocks:
> https://www.ti.com/lit/pdf/snoa653
>
> Neil
>
> On Sat, 31 Oct 2020 at 00:09, Pete Hartman <pete.hartman at gmail.com> wrote:
> >
> > 1) Is there anyone with experience or a pointer to a description of how
> the Serge '73 R7 envelope generator works?  Basic googling gets me various
> summaries of Ken Stone's page where "a little on how it works" is just the
> schematic.  Got that, don't grok it in the slightest...
> >
> > ...Because I don't really "get" Norton Amplifiers.  (I have been able to
> repair VCS' in the past but leaned very heavily on Tim Stinchcombe's
> description of how it worked).  I mean yes, I understand logically "current
> differencing" but in practical uses I can't look at a topology and say "oh
> yes, this is an inverter/summer with gain X" the way I can with a standard
> Op Amp.
> >
> > So
> >
> > 2) out of all of the various circuit simulation tools that have been
> discussed, which one or ones has a decent Norton Amp simulation?
> Simulation is usually my go to with circuits that don't follow "standard"
> often used topologies (standard like an expo converter, or
> integrator/differentiator, etc).  I'm one of those who has long leaned on
> the Falstad javascript simulator, and they do NOT have a Norton Amp (at
> least not as far as I could tell, no promises that I didn't miss something).
> >
> >
> > I've got one of ZThee's 73-75 panels and none of the three EGs will
> cycle in the usual way.  Power looks good, components have not been 100%
> verified but everything I've checked directly against the circuit appears
> to be correct.  Nothing is hot.  Soldering is solid (I resoldered a few
> joints here and there, but mostly out of an abundance of caution).  None of
> the usual first step troubleshooting methods has borne fruit so I'm now
> into "ok I have to understand the circuit well enough to know what each bit
> of it SHOULD be doing when I have end connected to start or cycle."
> >
> > Thanks!
> >
> > Pete
> > _______________________________________________
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>
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