Amps
[Top] [All Lists]

[AMPS] New 572B's needed Any thought of what Brand?

To: <amps@contesting.com>
Subject: [AMPS] New 572B's needed Any thought of what Brand?
From: km1h@juno.com (km1h@juno.com)
Date: Fri, 5 Mar 1999 16:38:44 -0500


On Fri, 05 Mar 1999 08:18:02 -0500 Scott Gordon <kq8rp@primenet.com>
writes:
i
>The Chinese Star tubes require the automatic tuner in the transceiver
>to get above 200 watts output.  Even with the transceiver tuner in
>line, they put out only about 700 watts.  The Chinese tubes clearly
>are inferior.  At least, this set has a problem.

The original buyer went on price only, not quality.  There are Chinese
versions that equal or exceed Cetron.




>
>In the past, I have owned Heath SB200 amplifiers, also with Cetron
>572B tubes, and can attest to the consistent performance of those
>tubes from one to another.
>
>I can buy 4 Cetrons that are a known quantity.  They cost more, and I
>don't really know who sells these any longer?


Richardson owns Cetron. Take it from there. They also helped to destroy
Eimac.



>
>I can save some dollars buying the Svetlanas.  But to me, the 
>Svetlana
>tubes may be just as risky as the Chinese tubes.

Svetlana is much worse than any others, stay away from them except for AM
modulators.


>
>Please answer a few questions for me.
>
>o I can buy more Star tubes and take a chance, but experience says
>  that is what I would be doing.  Please comment based on your
>  experience?
>
>o Should I buy Svetlana tubes that RF Parts promotes?


I sell my own brand from a select Chinese factory. A full 1yr no
questions asked warranty.  Got so pissed off at the other versions I
spent considerable effort doing it "my way"

I can sell you a guaranteed matched quad for $230 shipped. I challenge
others to "show the beef".
No magazine advertisements, no BS, my customers are mostly contesters and
other serious users.

>
>o Why should I feel comfortable that they have the same consistent
>  quality as the Cetrons?

There are many competing factories and some US distributors have name
brands based upon price only.


>
>o Do you know of any reason Svetlanas would not work well in the
>  Clipperton L?


Do you have enough time for me to answer that ?? Untamed prasitics are
just the first reason. I was a Svetlana dealer, no longer.

>
>o Should I expect the Svetlanas to be as good as the Cetrons?

See above.


>
>o Anyone else using the Chinese Star tubes, but do you have any
>  experience that will help me understand them?

Star is an entry level brand, also privately labeled by some distributors
selling price only.


>
>o What about this talk about a matched pair? Is it worth the extra
>$$$$????

In the Clipperton L  it can be an important issue. In a 2 holer, probably
less important.


>
>  Supposedly a matched quad, the Chinese 572B tubes were marked with
>  handwritten figures of 103, 125, 126, and 131.  By itself, the one
>  marked 103 produced 30 watts out for 100 watts in and clearly has a
>  serious problem.  The other three each produced 200 watts when
>  tested one at a time in the same socket.  All the Chinese tubes,
>  either together as a quad, or one at a time, required the
>  transceiver antenna tuner to be used.


Unknown markings and probably based upon a static test only, if even that
much. I have purchased/evaluated a few brands that the markings show no
bearing upon matching, etc.

>
>  The old Cetrons in the same one-at-a time test situation offered 
>250
>  watts, 250 watts (requiring the tuner), 350 watts and 350 watts.
>
>  Why would 2 year old Star tubes have such a bad input impedance as
>  to require an antenna tuner between them and the transceiver?

Several reasons. I could test, evaluate and mark any that you wish to
send...any brand.
I have a modified Clipperton L and SB-200 here that I use as test
platforms.


>
>o Besides the lower output and the requirement for the tuner, is 
>there
>  any problem running the Clipperton L with the 3 Star 572Bs that 
>have
>  reasonable output?


No problem except the slight loss in output C and keep the drive below
100W. 


>
>Thank you in advance for your assistance as you guide me in my
>probable purchase of 572B tubes.  Thanks Scott KQ8RP


There are a few other simple mods to improve the L performance, I can go
into that later if there is enough interest.

73  Carl   KM1H


>
>
>
>
>--
>FAQ on WWW:               http://www.contesting.com/ampfaq.html
>Submissions:              amps@contesting.com
>Administrative requests:  amps-REQUEST@contesting.com
>Problems:                 owner-amps@contesting.com
>Search:                   http://www.contesting.com/km9p/search.htm
>
>

___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]

--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm


<Prev in Thread] Current Thread [Next in Thread>