In reference to the question on the 3CX1200Z7 tube:
I asked Ted Henry about the 3CX1200Z7 and he called Eimac and I quote
"Eimac swears to us that the 3CX1200Z7 is not being discontinued. "
The 3CX1200A7 as used in the HENRY 3K Classic & Premier and 5K Classic, as
well as the 3CX1200D7 as used in the HENRY 3KD Premier (desktop, this tube
is slightly shorter) are good choices for rugged dependable power.
A couple of points about these tubes vs the 3CX800A7 (used in many small
light weight amps)is that plate voltages can be more than twice as high in
the 1200 as for example the 3CX800A7 which only allows 2250VDC and again as
compared to the 3CX800A7 the 1200 has a 50 watt grid, the 800 only a 4 watt
grid. Most amps running the 800 use elaborate protection schemes which
unnecessarily add to the cost and complication of an amp.
Also, the 1200 is instant on and the 800 is a wait for warm-up tube.
With the 1200 being instant on, you can turn the amp on and off as you wish
and never miss a contact.
I have thousands of QSO's on my HENRY 3K Classic X MKII with the original
3CX1200A7 tube. I run RTTY in contests at full legal limit and the amp
doesn't even breathe hard! I don't hesitate to turn the amp on and off as
needed (I pay a big enough electric bill already!).
See http://radiodan.com/Henry/misc/Radiodans_3K.htm
73, Dan Magro W7RF, (member SCDXC, SCCC)
Rugged, Reliable Henry HF Amps are "Instant on" for RF Power now!
DXers/Contesters/Ragchewers get your HENRY from RADIODAN for LESS!
***Subscribe to the HENRY reflector at www.qth.net <http://www.qth.net>
***
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> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of Bob Marston
> Sent: Tuesday, October 06, 1998 11:58 PM
> To: john merryman
> Cc: amps@contesting.com
> Subject: Re: [AMPS] What Tube for Home brew
>
>
>
> At 02:24 AM 10/6/98 -0700, you wrote:
> >
> >I am considering building a new amp, we seem to have a good choice of
> >tube. Which would the panel reccomend
> >
> >from these
> >
> >4cx16000, 3cx1200z7, 3cx800, 4cx800, I would prefer to select the tube
> >that will be readily available in the future, since many of the
> >
>
> Hi John
>
> Well as to the 4CX16000 Don't you think that's overkill for a 1500 watt
> amp. In all seriousness the 4CX1600B is a nice tube and George Daughters
> has built a real nice amp around one. A pair of 4CX800As will have higher
> filament thermonic emission.
>
> After inquiring with Eimac on my own future amplifier project I was told
> that the 3CX1200Z7/YU181 is no longer manufactured. A newer
> version with an
> improved anode dissipation head is being made under the designation
> 3CX1600Z7/YC229. The distribution rights were given exclusively to Vernon
> Howell of Howell Engineering. I wrote him to obtain a data sheet. The most
> significant piece of data is the price. $687.00 And who knows how long
> Eimac will produce them.
>
> For that type of money you can obtain a 4CX5000, a socket and a screen
> supply. You'll have a more durable bottle with more headroom that will be
> around for many years to come. So you have to throttle it back to get 1500
> watts out.
>
> If the price of amplifier tubes seems out of kilter with the rest of the
> market your right. Richarson Electronics in the late 70s was convicted of
> Federal AntiTrust violations regarding the distribution of Power
> Amplifier
> tubes which were exclusive and monopolistic. The effects of which
> are still
> being felt by Hams today.
>
> 73s
> Bob Marston K1TA
>
>
> --
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>
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