[AMPS] Re:

w8jitom@postoffice.worldnet.att.net w8jitom@postoffice.worldnet.att.net
Mon, 16 Jun 1997 22:21:22 +0000


> From:          Rich Measures <measures@vc.net>
> >Rich comments;-
> >
> >>  The statement that I did
> >>not buy is that drawing grid current (Class AB2) decreases IMD.  I use
> >a
> >>Class AB1 amplifier, and I know that such a statement is unsliced
> >>bologna. ..... AB2=doo-doo.

Peter said....

> >Then my spectrum analyser is a liar.  ...........

Rich said...
.
> Another scenario seems a bit more likely.    
> Rich---

Rich,

Peter is correct. If you owned proper test equipment, experimented,  
and made measurements of IMD, you would understand neither Peter 
nor his spectrum analyzer is not likely to be the "liar" you imply.

Class AB1 does not always guarantee better IMD performance. Even 
though your "on the air tests" may have indicated YOUR PA was cleaner 
when AB1, you should remember you insist on using a "crummy bias 
system".

With the stiffer bias system Ian suggested, your "big amp" might 
not have been such a splatter box at high drive levels. 

73, Tom W8JI 

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