[AMPS] G2DAF Circuit

[measures]

>
>"Does the fact you measured one bad sweep tube amp suddenly mean the DAF is
>considered good engineering? (I don't think so.)"
>
>I simply stated that some grounded grid amps, which happen to use sweep
>tubes, have poor imd performance, yet that does not mean that all sweep tube
>amps are unacceptable.  Rich measured one bastardized "DAF" amp for imd and
>feels qualified to condemn all of them.
>
>I do not object to a conclusion based upon either empirical knowledge or
>logic - even if I might disagree with it.  I do object to a conclusion based
>upon faulty logic and/or no empirical testing - even if I agree with the
>conclusion.
>
>Two tone testing of amplifiers will not show a possible defect in the "DAF "
>circuit.  In particular, the screen voltage will be held high.  Norm's
>bastardized "DAF" hung a large electrolytic cap. on the screen, which would
>destroy it as a linear amp - yet it could have passed a 2 tone test.  But,
>the fact that a "DAF" circuit passes 2 tone testing does not mean it will
>fail.  Other tests can be used to determine the qualities of the "DAF"
>circuit.  I understand tests have been done and posted to a website, yet no
>one seems interested in looking at empirical results.  The attitude of a few
>is "it cannot work, therefore any results which tend to indicate that it
>does are flawed".

The DAF works.  The splatter level of c. -22db is FCC-legal because it 
does not usually go outside the amateur radio band in use.  
>
>At least a few "modified" DAF circuits are in daily use in Sweden.  Tests
>have been made and posted, and other hams who seem competent, have listened
>and not heard objectionable splatter.  That may not prove that the "DAF"
>circuit is the best circuit to use, but it may cause one interested in
>scientific investigation to at least come up with a test acceptable to them
>to further investigate the amplifiers that are in daily operation.
>
Testimonials about the wonderfulness of DAF amplifiers from users reminds 
me of a religious cult.  Members  give positive testimonies supporting 
the founder of the cult - even though he practiced polyandry with the 
wives of 11 cult members.  

>To dismiss an idea for the wrong reason, or because of a lack of adequate
>testing or understanding, is perhaps as objectionable as listening to a lot
>of splatter.  In fact, it is much worse.  I have a neighbor who runs a
>4-1000 grounded grid, driven by a SB-200.  He overdrives everything and has
>horrendous buckshot.  But, even though I operate in the same dx window as
>he, it does not bother me that much.
>
>For me, splatter is less objectionable than a closed mind!
>
How do you feel about tetrode users who close their minds to the 3/2 
Power Law, Colin?  

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


--
FAQ on WWW:               http://www.contesting.com/FAQ/amps
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com