There is NO Clipper circuit in this Apache. The clipper tube was removed and the tube socket is empty. This seems to be what many did as a modification. I did have the redrawn schematic showing the mod but have misplaced it. Thanks for the assistance. 73, john, k5PGW
--- On Tue, 2/3/09, Peter A Markavage <manual...@juno.com> wrote: > From: Peter A Markavage <manual...@juno.com> > Subject: Re: [AMRadio] Ultrasonic feedback > To: amradio@mailman.qth.net > Date: Tuesday, February 3, 2009, 8:54 AM > The front panel "gain" control is for the speech > clipping gain. If you > turn it up too high, depending on the setting of the > "real" audio gain > control which is located behind the key jack, the modulator > will squeal. > This is barring any other electrical or component issues. > > Pete, wa2cwa > http://www.manualman.com > > > > > --- On Mon, 2/2/09, John King <k5...@yahoo.com> > wrote: > > > > > From: John King <k5...@yahoo.com> > > > Subject: [AMRadio] Ultrasonic feedback > > > To: AMradio@mailman.qth.net > > > Date: Monday, February 2, 2009, 9:56 PM > > > Can anyone direct me to a source of information > or a > > > tutorial on Ultrasonic feedback in modulator > circuits such > > > as that in the Heathkit Apache. > > > > > > My Apache modulator squeals when the microphone > gain is > > > raised and the modulator tubes draw a lot of > current. As > > > long as the microphone gain is kept very LOW the > current > > > does not take off and there is no squeal coming > from the > > > modulator section. I am going to go through the > section with > > > a screwdriver and a nut driver to tighten up the > grounds to > > > the chassis and tube socket. > > > > > > Ultrasonic feedback is a NEW phenomenon to me. > Someone > > > mentioned ferrite beads some time back. Thanks > for reading. > > > 73, John, K5PGW > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: > http://www.mail-archive.com/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to > amradio-requ...@mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: > http://www.qsl.net/donate.html ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
