I am about to retire and hope to find some time to build some amplifiers.
It has been difficult retiring after an 40 year engineering career. I love
desinging
and building stuff.
I think my first will be some 4CX250B grounded screen grid and
control grid connected to cathode. Should have very low distortion.
But low power gain as well. Maybe around 5 or 6dB.
The second will be a pair of 250TH in grounded grid like I ran as
a teenager. It was so cool. But I only had 2kV plate voltage back then
for that rig.
I really want to make an amplifier with my 2000T. Grid driven naturally.
That one would be really cool. Just think of how big that tube is.
73
Bill wa4lav
________________________________________
From: amps-bounces@contesting.com [amps-bounces@contesting.com] On Behalf Of
Jeff Blaine [keepwalking188@yahoo.com]
Sent: Monday, November 14, 2011 3:57 AM
To: Charles Harpole; sre.1966@gmail.com; amps@contesting.com
Subject: Re: [Amps] What type of amplifier is best
Charles,
I have the 998 and used it for quite a long time in RTTY contesting when I was
running non-resonant antennas. In one case I had
loaded 1KW on 160m to run the 160m ARRL CW contest - the antenna tied to it was
a loaded 80m dipole. I abused it quite heavily and
only had one problem related to poor soldering of the toroids to the main PCB.
For the price, I think it's a very good value. Albeit with the usual MFJ
cautions to check the soldering work for the hand-assembly
part - same as with all the other MFJ gear...
73, Jeff ACØC
www.ac0c.com
-----Original Message-----
From: Charles Harpole
Sent: Monday, November 14, 2011 2:39 AM
To: sre.1966@gmail.com ; amps@contesting.com
Subject: Re: [Amps] What type of amplifier is best
Hey Shon, As an owner or former owner of Heath SB-220 and SB-230, Henry floor
model 2K, TL-922, National NC-2000, Alpha 76A, Alpha
76PAC, two Alpha 87a, Titan One, Dentron DTR-2000, three ICOM IC-2KL, and
Collins 500 watt version, I can speak with some awareness
of amps....hi....
Fact #1 is to get an amp that has either the 8877 tube or the 3-500Z because
these tubes appear to have a long future availability
due to continued production or so many held as spares. Avoid the other tubes
unless u can get spares yourself and hold them.
Fact #2 is selecting a key-down amp for which Alphas are known for. I do not
recommend the 87a as being too automatic and quirky
but any any of the others is close to the best one can buy. True as new or
used. All amps need watching keeping the grid current
down and they may last forever.
Fact #3 is to decide on tube or solid state. The Tokyo HiPower units, for
example, are quite promising solid state which offers
some advantages which u can see. An amp which matches your exciter could be a
plus like Yaesu or ICOM units. ALL solid state amps
must have a following antenna tuner, hopefully automatic. And because u have
already automated your antenna tuning, perhaps that
will help u make a decision.
>From you, I would love to know if the MFJ-998 automatic antenna tuner sold as
>a 1.5 KW unit will actually handle that power and
>under less than ideal situations. Please tell me.
Used amp notes.... Henry s are very well made but their p.s. tend not to
support what you need. Any Alpha as noted above are
dependable year in and out.
Good luck and as always, Life Is Too Short for QRP.... 73,
Charles Harpole k4vud@hotmail.com
> Date: Thu, 10 Nov 2011 20:54:10 -0700
> From: sre.1966@gmail.com
> To: amps@contesting.com
> Subject: [Amps] What type of amplifier is best
>
> Hello all.
>
> I know I am revealing my ignorance, as most of what is on this list goes
> above my head. However, I am looking to buy an amplifier, full legal limit
> (1500 W -- US or more wattage -- I mean one which will yield an SSB
> continuous wave carrier at 1500 W for a reasonable amount of time to carry
> on QSOs), and wonder which might be best for me in my situation. I am just
> looking for something that will endure through years of use. I must admit
> I do not know anything beyond this. Perhaps you could ask me more
> questions about specific use to help you narrow down, if necessary.
>
> A couple I have been looking at buying are the following: Ameritron
> AL-1500, AL-1200, and AL-82. I'm open to others, as well. I know many of
> you are experts at making your own. Perhaps I would even go this route, if
> it would save me enough money. I have done plenty of building of
> electronic equipment in the past -- just not amplifiers.
>
> I am using an FT-857D, fed with about 100 ft. of LMR-400, attached to an
> external remote automatic antenna tuner, MFJ-998RT, and an MFJ-2990 43 ft.
> vertical antenna (all of which can handle the 1500 W or more).
>
> Again, forgive me for my ignorance; I'm sure I will get a few comments
> like, "go to school for a few years" or some such. I'm sure this would
> help, but in lieu of this, perhaps you could help me with a few ideas :).
>
> Thank you all,
>
> 73 de K6QT, Shon
>
>
> --
> Shon R. Edwards,
> Amateur call: K6QT
> 1039 N 2575 W
> Layton, UT, 84041-7709
> USA
> e-mail: sre.1966@gmail.com
> phone: (801) 444-3445
> cell: (801) 336-7635
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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