[AMPS] Re: G2DAF Amps Circuit

[measures]

>
>Tom- I have heard little good about it, either, except that the "real"
>G2DAF circuit depended on a particular tube to work acceptably, and that
>the units Rich is mad at, and talks about, were NOT the real thing. 

The original circuit was tried by two of the three users in California.  
There was a problem with not enough screen volts.  Their mod helped.  The 
last fix was to regulate the screen with a shunt regulator.  

>THis is
>from his own words, just put in more blunt form. He has not, apparently
>ever heard a real one. 

 The W6CHR version was apparently the original DAF circuit.  This is the 
amp. that produced splatter from 3980 to c. 3810 KHz.   Is this awesome 
or what?

> Each one he has heard, from his posts, had been
>"improved" by someome otherwise well known for feculence, already.
>
yea, verily. 

>Enough- I am certainly NOT pushing that circuit, when many better are around.
>
true enough, Bill.  However,  FCC rules permit any amount of feculence 
provided it does not go outside the amateur service band.  
>
>At 01:00 PM 10/25/00 -0400, you wrote:
>>Hi Bill,
>>
>>> Previous posts indicate that the numbers Rich used below were NOT for a
>>> G2DAF Amp, but for a "bastardized" version. Rich has a "Thing" against the
>>> so-called G2DAF, and his comments are to be taken with caution.
>>> 
>>> Bill-W4BSG
>>
>>I don't think the G2DAF is a good system either. It has to be, at 
>>the very least, very unreliable for IMD quality.
>>
>>It does everything wrong I can possibly imagine. It loads the exciter 
>>with a time-varying and power sensitive load, the screen voltage 
>>moves all over the place, and there must certainly be phase-shift 
>>between the screen voltage and the drive voltage.
>>
>>Probably the only thing that "saves it" in some cases is the high 
>>amount of negative feedback.   
>>
>>I'm sure there are cases where it will work, but then I've even seen 
>>class C PA's produce "acceptable" IMD at certain power levels and 
>>certain tuning conditions.
>>
>>IMO, the fewer G2DAF systems on the air the better off we all 
>>are....even if some seem to be "OK". It has to be one of the 
>>poorest circuits available for a linear amplifier, short of out-and-out 
>>self-biased class C.
>>
>>
>>73, Tom W8JI
>>w8ji@contesting.com
>>
>>
>-
>Bill Aycock   ---   Persimmon Hill 
> Woodville, Alabama, US 35776
> (in the N.E. corner of the State)
>      W4BSG   --   Grid EM64vr
>        baycock@HiWAAY.net
>             w4bsg@arrl.net
>
>--
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>


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


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