[Heathkit] foldback

Jim Brannigan [email protected]
Fri, 10 Oct 2003 05:16:45 -0400


Agree with Mr. Measures or not, his WEB site contains valuable information
for the Heath amp. owner.

Jim


> You may want to read the series of rebuttals by real engineers in QST
about
> the Measures articles. And that he has been banned from future publication
> there.
> I consider most of his parasitic theory pure garbage and have proven it
time
> and again to skeptics. This is old news as it took place on the AMPS
> reflector several years ago.
>
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- 
> From: "David Cook" <[email protected]>
> To: "'Jim Brannigan'" <[email protected]>; <[email protected]>
> Sent: Tuesday, October 07, 2003 9:48 PM
> Subject: RE: [Heathkit] foldback
>
>
> > Wow, what a great paper! I recently acquired the first amplifier I've
ever
> > owned, an SB-200. I put in all the Harbach mods, but still didn't
> understand
> > much about it. Many of Rich's explanations of the design decisions and
> > performance considerations for the SB-220 apply to the SB-200. Thanks
for
> > posting this link. I'm going to fire off an e-mail of appreciation to
Rich
> > as well.
> >
> > 73, Dave, WA�TTN
> >
> > > -----Original Message-----
> > > From: [email protected]
> > > [mailto:[email protected]]On Behalf Of Jim Brannigan
> > > Sent: Monday, October 06, 2003 2:38 PM
> > > To: Hotmail; [email protected]
> > > Subject: Re: [Heathkit] foldback
> > >
> > >
> > > This is Rich Measures' site.  There is a wealth of information on the
> > > SB-220.
> > > http://www.somis.org/sb220ci.html
> > >
> > > The SB-220 was designed when most exciters were tube based
> > > with a pi-network
> > > output.  The pi net output is able to match a wide range of
> > > loads and the
> > > input impedance of the amplifier was not a serious design
> > > consideration.
> > > Many Solid state exciters are not as forgiving and some
> > > attention to the
> > > amplifier input impedance is necessary.
> > >
> > > Jim
> > >