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. THis is
from his own words, just put in more blunt form. He has not, apparently
ever heard a real one. Each one he has heard, from his posts, had been
"improved" by someome otherwise well known for feculence, already.
Enough- I am certainly NOT pushing that circuit, when many better are around.
Bill
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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