Hi Carl,
Just a few thoughts came to mind.
I would asume the Chinese might have used the Russian (AKA Sevetlana)
design of 572B as their model and they had more gain than other mfgrs.
When Sevetlana first introduced them to the US markets it was observed
that they drove easier to greater output and were (under certin
circumstances and opperating conditions) not too stable at the upper HF
bands necessitating a change in cutoff bias and in some cases a change in
paricitic supressiors and some additinal stabalization methods to be
employed.
If you are running 2300VDC you should be running about 565ma of plate
current which would give you about 1300 watts input and for that input about
900watts output. If you meter is of normal accuracy then plus or minus 5
percent or more is not uncommon so to indicate "almost 1kw output" would be
pretty normal. PEP. They will take 2500 no problem but most older amps using
them tend to run closer to 2000 than 2500 and they get a bit "peppier" with
more voltage so if you are use to observing say an older SB200 with Taylor
or Cetron tubes of similar vintage then you are use to seeing more like 450
to 600 watts output (depending on age and emission).
Just as a suggestion you might observ the PC Plate supressors to make
sure they are in good shape and not showing signs of heating due to some
"undesired" output on some freq other than the primary which might be
showing up in the output and giving you a false reading. A wide range
receiver on scan using a sample probe into a dummy load and running reduced
output to prevent overloading the power supply can be used in a pinch.
For what its worth, I would just check to see the filament voltage is in
the proper range under load and button it up and enjoy the amp.
Best 73
Mike Baker K7DD
----- Original Message -----
From: "carl s." <carlseye@tampabay.rr.com>
To: <Amps@contesting.com>
Sent: Friday, September 08, 2006 2:45 PM
Subject: [Amps] amp tubes
> I have been working on an amp, fl2100B , and see something I can't
> believe.!! the amp has 2 ea. New chinese type 572B's.
> I have two output meters, both WM1 auteks.; With about 60-80 watts
> input I'm seeing almost 1 kw. *output*. Is this anywhere near logical
> ?? The HV is about 2200-2300 under load. !! It just doesn't seem
> possible, and I've never seen anything like this
> before !!!
> I've worked on many other amps ( similar ) and have never seen
> anything like that much output.!!
> BUT, I've never used *chinese* 572'B s either !!
> Do any of you have any spec's that might differ from the
> U S. ( IE ) taylor ,l or other mfrs. Specs as to the gain factors
> between the US and chinese specs'?????>
> I'd appreciate any info anyone might have !!!!!
> carl / kz5ca
>
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