[sdiy] EH frequency analyzer

[harrybissell at wowway.com]

Woops... What I posted had the 13600 and 13700 descriptions
backwards.

13600 - variable buffer
13700 - fixed buffer

Scott is correct
H^) harry




On Fri, 08 Aug 2008 07:17:44 -0700, Scott Gravenhorst wrote
> Tom Wiltshire <tom at electricdruid.net> wrote:
> >
> >On 8 Aug 2008, at 14:40, John Mahoney wrote:
> >>
> >> The Moogerfooger ring mod looks to be based on the LM13600. (Hey,  
> >> isn't the 13600 all but extinct? I wonder what Moog is using now in  
> >> these pedals. Maybe they've got a stockpile.)
> >
> >National Seminconductor still have the LM13700 listed. I never  
> >understood exactly what the difference was supposed to be between  
> >LM13600/LM13700 ( was 13700 a later upgrade?) but they seem to be  
> >pretty much interchangeable.
> >
> >T.
> >
> >(http://www.national.com/mpf/LM/LM13700.html)
> 
> It's been mentioned here that in the LM13600, Iabc has an effect on 
> the output buffer, whereas the LM13700 has a buffer which is 
> isolated from Iabc.  I just looked at the datasheets for both and 
> this is shown in the internal schematics of the parts.
> 
> Not sure _exactly_ what the effect of that is (thumping in a VCA?).  
> They are interchangeable in many apps, but not all.  In a pinch, if 
> one doesn't want the Iabc output buffer effect of the LM13600, I 
> think an external buffer can be used instead of the IC buffer to 
> emulate the LM13700.
> 
> -- ScottG
> ______________________________________________________________
> -- Scott Gravenhorst
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Harry Bissell & Nora Abdullah 4eva