When I built my pair of 4-1000`s (GG/1972) I used very short plated strap
for the plate leads and located the parasitic supressor at the cathodes
...Worked fine on 10 &15 meters,at slightly reduced efficiency compared to
the lower bands....With 6400vdc on the plates, 35-50 watts drive easily
produced 1500+ output...The cathode imp.of two paralled tubes is much closer
to 50 ohms than a single tube (105 ohms) so a pair in a properly designed
circuit drive much easier than a single tube....That amp is still performing
at it`s new owners qth&I have long since moved along to the ceramic
triodes...Seasons greeting everyone and hope for a great new year, Jim
K7RDX..
----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
To: <robby@route2.pe.ca>; "'Pat Barthelow'" <aa6eg@hotmail.com>;
<amps@contesting.com>
Sent: Sunday, December 23, 2007 1:01 PM
Subject: Re: [Amps] What is the best way to run a pair of 4-1000 tubes
> The 4-1000A is rated far beyond 30 MHz. The problem is mostly in HF
amplifiers that Plate current paths get to be long thus lowering the VHF
parasitic frequencies so that choosing a suppressor that works with out
absorbing too much HF RF power is a bit more difficult.
> Anyway, that is the only problem I have encountered with 4-1000A tubes on
10 meters.
>
> 73
> Bill wa4lav
>
> ________________________________________
> From: amps-bounces@contesting.com [amps-bounces@contesting.com] On Behalf
Of r2robby [robby@route2.pe.ca]
> Sent: Sunday, December 23, 2007 3:35 PM
> To: 'Pat Barthelow'; amps@contesting.com
> Subject: Re: [Amps] What is the best way to run a pair of 4-1000 tubes
>
> Pat,
>
>
>
> I agree that using a single tube makes more sense. You still may have a
> performance issue on 10M but if you are careful maybe not. The bottles I
> used were pulled from navigational aid sites but I think broadcast
> transmitters used them too. They pull them after a period of time. Or if
> the emission is down. There is still plenty of power for amateur use. I
> know the 3-1000Z was used in commercial amps because I have one in my
> basement. This tube is harder to find.
>
>
>
> I used to know more about this stuff. But I forgot.
>
>
>
> Happy Christmas everyone!
>
>
>
> -Robby
>
> VY2SS
>
>
>
> From: Pat Barthelow [mailto:aa6eg@hotmail.com]
> Sent: Sunday, December 23, 2007 1:03 PM
> To: robby@route2.pe.ca; amps@contesting.com
> Subject: RE: [Amps] What is the best way to run a pair of 4-1000 tubes
>
>
>
> Another question(s) re 4-1000As. I see them pretty regularly at ham
swap
> meets, used and cheap. Often with the carbon coated brown "tint" on the
> inside of the envelope. Does anyone know what the likely commercial
> application is/was, that pulls, floating around the ham community were
used
> in? Military? Broadcast radio? What was the Pulse application?
> Someone mentioned in the past, that Broadcast TX's that used to yield
> 4-1000A pulls, have evolved towards solid state finals, and the supply of
> pulls, has/is drying up.
> Is the carbon deposit an indication of extreme age or hard running, and
> probable near-end of life issues? Or, can it exist, and the tube still
be
> used in Amateur Service, happily ever after? What are the likely failure
> modes for the 4-1000?
>
> Did the 3-1000Z ever have a commercial application?
>
> If the pulls have been sitting around for years, or decades, are they
> subject to
> the gas ingestion problem across their pin seals, over time of stored,
> non-operation? Can you condition them with heat, but reduced B+ to
degass
> them?
> I havent looked for one, but is there usually a manufacturer's date code
> printed somewhere on, or in the tube?
>
> BTW, I have an Eimac, aluminum SK-5?? air blower socket for the tube,
> surplus to my needs, in case anyone is looking.
>
>
> Merry Christmas,
>
> All the Best, 73,
> Pat Barthelow aa6eg@hotmail.com
> http://www.jamesburgdish.org
> Subscribe: http://bambi.net/jamesburg.html
> Jamesburg Earth Station Moon Bounce Team
>
> > From: robby@route2.pe.ca
> > To: amps@contesting.com
> > Date: Sun, 23 Dec 2007 12:34:06 -0400
> > Subject: Re: [Amps] What is the best way to run a pair of 4-1000 tubes
> >
> > I built a grounded grid amp a few years ago....um..I guess 20..and used
a
> > pair of 4-1000PRs. I built it with RTTY contesting in mind. I used a
> > separate filament transformer and B&W filament choke for each tube and
had
> a
> > second blower that could be brought on line for RTTY. A pair of Hammond
> 795
> > transformers in the P/S. It loafed at the limit on the low bands.
> >
> > Unfortunately, even though I built it in a big box and was very careful
> > about stray capacitance in the output, I saw greatly reduced output on
10
> > meters and also on 15. The output capacitance of these tubes is far
beyond
> > what is necessary to resonate on the upper HF bands and still see the
> proper
> > plate load impedance. 7.6pf per tube for a total of 15.2 on the pair. I
> > assume this is because the screen grid is in very close proximity to the
> > anode.
> >
> > But boy did it like 40M! It is currently sitting idle at VE7ZZZ.
> >
> > Get a triode if you want a GG amp. The 3-1000Z has 0.12pf per tube.
> >
> > If you are stuck on using the tetrodes, and want 10 and 15 meters I
guess
> > you need to run them in another configuration.
> >
> > I often wondered what would have happened if I had let the screens
float.
> > Or tied them to the anode. Something bad probably.
> >
> > -Robby
> > VY2SS
> >
> >
> > -----Original Message-----
> > From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
On
> > Behalf Of amps-request@contesting.com
> > Sent: Sunday, December 23, 2007 11:17 AM
> > To: amps@contesting.com
> > Subject: Amps Digest, Vol 60, Issue 34
> >
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