end
Barry Kirkwood PhD ZL1DD
Signal Hill
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: Barry Kirkwood <bjk@ihug.co.nz>
To: Randall D. DuCharme <randyd@specent.com>
Cc: <amp@contesting.com>
Sent: Friday, 27 October, 2000 2:04 PM
Subject: Re: [AMPS] G2DAF
> Goodonyermate!
> (This should really put the braves in orbit!)
> The "ZL Linear". Variations published in US in CQ Magazine and Cowan group
> ( ? Don Stoner W6TNS) SSB handbooks ca 1960.
> The definitive article:
> Earnshaw, L. ZL1AAX , Simple Sideband, Part VI, Break-In (NZART Journal)
> October 1958 pp.20-22
> ".....but first I must warn you that this amplifier dies everything that
the
> good book says you must not do....It is simply a Class C type type of
final
> with clamp tube screen voltage control...."
> (Circuit shows 813, parr tuned ckts grid and plate, neut cap plate to
bottom
> of grid ckt, thence to E via 500pf. RFC via 10K grid leak to mA meter grid
> current to E. Junction RFC 10K to grid 6F6 , cathode earth, screen and
plate
> tied. 40K to anode 6F6 from plate volts, thence to screen 813 bypass to E
> 0.002. Plate series feed bypass also 0.002..
> "Clamp tube must not clamp too heavily......I found that with most final
> tubes the 6Y6 was too severe in its clamping action....gives distortion
at
> lower levels..."
> "Plate volts 1000
> grid leak 10,000
> screen R 40,000
> clamp tube 6F6, 12A6 [ 42!]
> Standing plate I 40-50mA
> with 3mA grid current with carrier wound in, or tone modulation, plate
> current 120-150mA.
> On voice modn plate current risies to aaprox 100ma.
> Different clamp tubes give different standing currents.
> Plate tuning C: 80m 240pf (et seq)."
> Used with 813, 4-125, KT88, 807 at time of writing.
> Them were the days!
> 73 es Hohoho!
> end
> Barry Kirkwood PhD ZL1DD
> Signal Hill
> 66 Cory Road
> Palm Beach
> Waiheke Island 1240
> NEW ZEALAND
> www.waiheke.co.nz/signal.htm
> ----- Original Message -----
> From: Randall D. DuCharme <randyd@specent.com>
> To: Barry Kirkwood <bjk@ihug.co.nz>
> Sent: Friday, 27 October, 2000 12:42 PM
> Subject: Re: [AMPS] G2DAF
>
>
> > Barry Kirkwood wrote:
> > >
> > > Finding the G2DAF thread great entertainment.
> >
> > Me too, but also educational.
> >
> > > Who remembers the ZL linear?
> >
> > Not me. Just got into ham but am itching to build.
> >
> >
> > > Take an 813 (or two).
> >
> > How about 4? ;-)
> >
> > Seriously tho' I am looking for a sample circuit diagram of just this
> > type of amp. Web searches have turned up nothing and all of my
> > reference manuals are just too new. Have you any idea where I could
> > find one?
> >
> > Many thanks
> >
> > --
> > Randall D DuCharme (KD5IZI) Proud to be 100% Microsoft Free!
> >
> > Unsolicited commercial email (SPAM) received at this email address
> > will not be tolerated. All spam is subject to a $200 per incident
> > processing fee and possible legal action pursuant to US Code, Title
> > 47, Chapter 5, Subchapter II, p.227.
> >
>
--
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