Greetings Amp'ers:
Today I fulfilled a long time dream. I now own a real Alpha HF power
amplifier.
A ham within 1 hour driving time recently offered his Alpha 78 for sale at
a price I could afford. When I read his ad I immediately called him and
arranged to visit and examine the amp. It's cherry and works perfectly.
Serial Number 8355 with the Low Power Mod and an SO-239 on the RF Input.
I got it home, connected it and proceeded to make contacts on 75 SSB and 40
CW. Great signal reports. Good clean signals on both modes. Testing into a
dummy load, the amp easily produces up to 2 KW output on 80 through 15
meters with grid current well below 50 ma. I couldn't be happier.
Prior to visiting and buying the amp, I downloaded the manual and searched
the web for info on this model. I didn't find much. By most accounts it's
possibly one of the best amps ever made. Sure the tubes are expensive and
are on the verge of being discontinued but if the legend is true and I
don't abuse the amp, the tubes should last nearly forever.
So what suggestions do you have for a new Alpha owner?
Some I've read so far in my research:
Annual cleanings
Monitor the Grid Current
Keep the load SWR 1.5 to 1 or less
Keep the chimneys and anode vents clean
Are there others?
I have been using a Heathkit SB-221 with much success for quite a while. It
experienced the dreaded Glitch and blew a tube. I added Harbach mods and I
don't worry about such things any longer. Is the Alpha subject to the same
Glitch problem??? I did read where 24 MHz is not recommended because of a
HV plate choke resonance issue at 25 MHz.
Are there other mods recommended?
I await your advice.
Respectfully,
73,
Frank N. Haas KB4T
Florida
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