SB-221

[multi-volti at MULTI-VOLTI.COM]

It was a 5.1 V 10 W zener. Higher voltage pushes the bias closer to class
B...higher efficiency, higher distortion, harder to drive. I knew a guy who
used an 866A for cathode bias drop (about 15 V), at least on CW, and it
flashed purple with CW (yes, it was mounted externally with a C-clamp). I
don't think it worked well on SSB.

Murray
----- Original Message -----
From: "Mark Graalman WB8JKR" <wb8jkr at JUNO.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Wednesday, August 14, 2002 4:12 PM
Subject: Re: SB-221


> The amp will work fine without it, but the idle current will be
> higher than normal increasing heat from the tubes and the
> power supply, I think it was a 6.8 volt 10 watt zenner, but I
> don't remember for sure. At any rate, a 6.8 volt 10 watt
> device would work fine.
>
> 73,  Mark  WB8JKR
>
>
> On Wed, 14 Aug 2002 09:42:06 -0800 Tom Elmore <tom at TELMORE.COM> writes:
> > I have a SB-221 amplifier that is missing zener diode ZD-1 and it
> > appears it may have never been installed
> > although the amp seems to put full power out. The only thing I don't
> > seem to have is idle plate current that the book calls for. Any
> > ideas ?????
> >
> >
> > Thanks
> > -Tom / KA1NVZ
> >
> > -----------------------------------------------------------
> > 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
>

-----------------------------------------------------------
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