> Could it be that "self-oscillation" at or near the operating frequency and
> VHF oscillation (parasitics) are rooted in the same mechanical design and
> layout limitations, and depending on the accuracy of the physical design,
> oscillations may occur 1) at or near the operating frequency, 2) at VHF
> frequencies if ample gain exists, or 3) no oscillations at all if the
> design and layout is nearly perfect? If so, can't we simply view the
> suppressor as a device to temper slight layout flaws, slight
> inconsistencies between amplifier wiring and mechanical geometries from
> one production unit to the next, and slight inconsistencies in tube
> manufacturers and processes?
That's exactly what a suppression system does.
> > You see tubes like the 8877 or 3CX800, or 3CX1200Z7 often don't
> > require any suppression at all....or at the best minimum
> > suppression.
>
> Not on the amps I see. I see some form of suppressor on all the 8877 and
> 3CX800-based HF amps in current production. Is anyone presently producing
> an amp utilizing the 3CX1200Z7?
Not that I know of.
By the way, many amplifier designs are done they way they are
because people "perceive" it should be done that way.
Look at the capacitance values of blocking capacitors as an example.
73, Tom W8JI
w8ji@contesting.com
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|