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A balanced 12AX7 based buffer

Started by Les Cargill May 11, 2018
 Les Cargill wrote:
> > >> > >> Phil Allison wrote: > > > >> > > > > ** The design was a published as a project in Electronics Australia > > in 1998 - it proved very popular. Easy to build, considerably lower > > cost than commercial alternatives plus better performance. > > > > > > Yeah, that looks like a very easy build. I've bookmarked that. Thanks, > Phil. > > GND2 is case ground, and isolated from signal ground? >
** Correct. This is needed for use with PA systems to eliminate hum loops, with sources that are mains earthed like keyboards and guitar amps. The original EA article is here, starting on P52. http://americanradiohistory.com/AUSTRALIA/Archive-Electronics-Australia/1998/EA-1998-02.pdf .... Phil