[AMPS] Purchase Recommendation?

[Paul Christensen]

>Paul, Which amplifier(s) are bothered by these "spikes"? Sounds like you
>really went to great difficulty to modify your very FB Ten Tec transceiver
>to allow use into some amplifier that didn't like these spikes?

None of my Alpha amps are bothered by the leading edge power spike.  It was
something I noticed in my attempt to clean-up the leading edge of the Omni
Six in order to mainatin leading and falling edge CW waveform symmetry.  As
shipped, the Omni's leading edge is extremely sharp and fast; mine had a
1ms rise time, and subjectively, it was very "clicky."  The Omni
incorporates an adjustable integrator circuit to control the waveform, but
it is only useful on the trailing edge of the waveform.  As has already
been indicated, the transceiver's ALC circuitry will oftentimes create the
leading edge power spike, particularly at lower power levels...the level
needed to drive many amps.  

Some transceivers, including my new Kachina 505DSP, allow you to set gain
independently of output power.  On other transceivers, this is labeled as
the drive control.  However, I notice that when these transceivers are
operating just under the ALC's operating "knee," the drive into the amp
changes as the transceiver's output stages increase in temperature.  For
me, this translates into creeping up the drive or gain control after the
first one or two QSO exchanges in order to maintain consistent legal output
power.  

On all three of my Alpha's (PA-70V, 77Dx, 87A, even the ACOM 2000A) this
isn't a problem.  It's more of an obsessive-compulsive trait of mine that I
love to hear and see the effect of a good CW waveform on my station
monitor.  I could have just as easily left the status-quo...must have been
my early musical training that made me this way!

Earlier today, someone replied to my message and had construed the meaning
to the systematic ALC approach sometimes used between the transceiver and
the amp.  I have only been referring the transceiver's internal ALC
circuitry.

-Paul, W9AC



--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm