[AMRadio] re: Apache audio not good

[russ dworakowski]

Hey it works.  Russ


>From: "John Coleman" <jec at pctechref.com>
>Reply-To: amradio at mailman.qth.net
>To: "AMRadio (E-mail)" <amradio at mailman.qth.net>
>Subject: RE: [AMRadio] re: Apache audio not good
>Date: Mon, 15 Apr 2002 12:21:57 -0500
>
>Good Point:
>	Negative feedback is a real good idea and I have found a few good points 
>to
>follow.
>
>1.  Don't over do it.
>     Make the Class A stages as distortionless
>     as posible without feed back other than
>     unbypassed cathode resistors.
>
>2.  Don't try to include too
>     many stages in the loop.
>
>3.  Power stages with unconstant loads
>     such as (DRIVERS for Class B)
>     need it the most.
>
>4.  Using the feedback points for in and out,
>     sweep the amp first for frequency responce
>     and make a graph.
>
>5.  Sweep again for phase shifts
>     and make a graph on transparence paper:
>
>6.  Overlay the graphs.
>
>7. Designe your feed back divider circuit
>    for the same responce curves,
>    or as close as you can get.
>
>These or just some of my findings
>and guides and certainly not writen in stone.
>
>Good Luck, John, WA5BXO
>
>
>-----Original Message-----
>From: amradio-admin at mailman.qth.net
>[mailto:amradio-admin at mailman.qth.net]On Behalf Of Gary Schafer
>Sent: Monday, April 15, 2002 9:58 AM
>To: amradio at mailman.qth.net
>Subject: Re: [AMRadio] re: Apache audio not good
>
>
>With a feedback circuit it is best to limit the frequency response at the
>high
>and low end of the feedback loop. This limits the amount of phase shift in
>the
>feedback circuit that can cause oscillation.
>
>73
>Gary  K4FMX
>
>
>AA8TV at aol.com wrote:
>
> > Hi Russ,
> >
> > One trick I used on the negative feedback circuit for my DX-100 was to 
>do
>the
> > voltage dividing first, and then de-couple the dc with a cap. This way 
>the
> > cap is a 50 volt part rather than a 1000 volt part. You can use a 100uf
>50v
> > electrolytic if you want to, it's easy on the pocket, and physically
>small. A
> > 100uf plus cap also helps in adding feedback on the low audio 
>frequencies.
> > The Apache uses the same mod iron as the DX-100. They both have a 500 
>ohm
>tap
> > to use for the negative feedback. I'll bet this would work in the apache
>as
> > well.
> >
> > 73, Ed
> > AA8TV
> > _______________________________________________
> > AMRadio mailing list
> > AMRadio at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/amradio
>
>_______________________________________________
>AMRadio mailing list
>AMRadio at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/amradio
>
>
>
>_______________________________________________
>AMRadio mailing list
>AMRadio at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/amradio


_________________________________________________________________
Send and receive Hotmail on your mobile device: http://mobile.msn.com