Lou,
The only problem I see in using more powerful tubes is the strain on the
components,
especially the HV transformer. The HV transformer is designed for the output of
two
572B's running at about 600 watts (or is the most I've seen from a set).
Heathkit
especially designed for an intermittent duty transformer, and it's design is
right on the
edge itself. Every transformer they designed was this way. Some might argue
they
were designed tougher, but I did some comparisons, and calculations using the
core
size, and they were smaller as compared to others. This can be seen in the
regulation
they have too. Of course if one intends to run SSB only, this would help by a
margin of
around 25%, or the transformer would run 25% cooler, and have around 25% better
regulation than on AM or CW. Generally an amps transformer is designed around
the
carrier and the peak power of AM or CW unless it's a SSB only amp. I'd watch
about
the transformer getting hotter using tubes with more gain than usual over this.
Tubes
can be replaced pretty cheap, but transformers are expensive.
Best,
Will
*********** REPLY SEPARATOR ***********
On 9/10/06 at 8:54 AM Gudguyham@aol.com wrote:
>In a message dated 9/9/2006 8:28:21 P.M. Eastern Standard Time,
>carlseye@tampabay.rr.com writes:
>
>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
>
>
>
>
>
>Carl, What band are you seeing this kind of output? I had a WM-1 in the
>past and I would not say they are the most accurate meter I have ever
>owned, in
>fact far from it. There are adjustments to "calibrate" it, but it tends
>to
>be a compromise along the bands. Likewise, I have never seen this much
>power
>from a pair of 572B tubes, but I have used MANY of the Chinese 572B tubes
>in
>my 6 meter conversions and they DO out perform ANY other brand of 572B
>including Cetrons. Though my experience with them is only on 6 meters
>which is
>the upper limit of which they will work, there is no doubt that the
>Chinese
>tubes make more power than others. I would NOT even attempt to use a
>Russian
>tube on 6 meters! Though I doubt the Chinese tubes have the quality
>control
>that the Cetrons did, I could imagine that some tubes may have more gain
>than
>others and perhaps you have gotten a "freak" pair that makes more power
>than
>most. At one time I did see about 800 watts out of one of my 6 meter
>SB-200
>retrofits on 6 meters and I was amazed at that. I obtained that with
>every
>bit of 100 watts of drive. You mention that you see this with only 60-80
>watts
>of drive, that makes me wonder. If you could possibly retest the output
>using another meter I would be curious to see what reading you get. When
>I
>tested the output of my 6 meter SB-200 conversions I did it into a Bird
>dummy
>load using a Bird 43 meter with a KW slug. I also used another meter to
>see
>what it said. Other meters were always close to the Bird numbers by
>single
>digit percentages. Now, it has been almost 3 years since I have used a
>set of
>Chinese tubes in an SB-200 on 6 meters, and perhaps NOW they have even
>more
>gain then they did then. I don't mean to doubt your claim, but I would
>see if
>another meter tells you the same thing. I do believe a test into a dummy
>load with more than one meter is in order. Report results if you can do
>such a
>new test. BOTTOM LINE: I do agree that the Chinese tubes have more gain
>then other types of 572B, and maybe they have just improved their
>product.
>Could be? 73 Lou
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|