SB-110A experiment

[Mark Graalman WB8JKR]

  I understand that Ron, but this is the audio output tube, it has
nothing to do with the BFO at all. My purpose in the trial
removal of the cap was to develop a slight amount of negative feedback
in the audio output stage. It certainly was a strange surprise to see
that happen! The BFO is a completely separate tube, on the same circuit
board, but about 3 inches away from the audio section.
 I guess this might be one of those thing where if I didn't see it for
myself
I'd never believe it.  ;^)

Mark  WB8JKR

On Wed, 25 Jun 2003 08:56:22 -0400 Ron <ra.ah at RCN.COM> writes:
> Mark Graalman WB8JKR wrote:
> >
> >   I have  something for you SB-110A owners to try when you
> > have a few spare minutes to screw around.
> >
> >  I have a SB-110A here that works perfectly, and has no problems
> > electrically. However sometime ago while doing some experimenting
> with
> > the rig I discovered that if the cathode bypass capacitor (C67) on
> the
> > audio
> > output tube V6 is removed the BFO will stop. I found this rather
> > astounding
> > and never did really determine why. Just curious if this happens
> with
> > other
> > 110A's or if I just have a sleeping gremlin. Checked the board
> grounding,
> > tried different ground paths etc, nothing changed anything.
> >  I put the cap back in and everything works fine.........go
> figure.
> >
> > Mark  WB8JKR
>
> I am not familiar with the circuit, but if the tube
> is in the BFO loop, I'd expect this behavior. Removing
> the cathode bypass cap substantially reduces the stage
> gain.
>
> -- Ron
>
> -----------------------------------------------------------
> This list is a public service of the City of Tempe, Arizona
> -----------------------------------------------------------
>
> Subscription control -
> http://www.tempe.gov/lists/control.asp?list=HEATH
> To post - HEATH at LISTSERV.TEMPE.GOV
> Archives - http://interactive.tempe.gov/archives/HEATH.html
>

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html