>
>I would say that the 160 meter padding caps on the tune and load are
>changing values due to heating....Most likely the load padders.
>
? the most likely answer. It could also be the Tune-C padders because
the current burden is virtually equal. To minimize tank drift, do not
tune up locked key. Also, the 800a7 has to be derated from 800mA to
600mA for locked key. Another prob. is that HV sags unrealistically
during locked key. For virtually all ssb amps, locked key is not where
one should be.
>My home brew "titan" has exactly the same symptom. (Same tank, same caps,
>same tubes). The tubes are new, and the filament voltage is right on spec.
>
? With barium migration there is a slow drop in anode current as the
grid temp rises. . With a drifting tank, anode current is virtually
constant. The great mystery is why the Titan's designers failed to read
the specs from the cap. manufacturer.
cheers, Jim.
I don't think the designers of the Titan read any specs on any of the tank
components. The first time I saw a Titan with the lid off was two years
ago in Dayton when the prototype of the "Titan II" was unveiled. I was shocked!
(no pun intended) I have seen more robust tank components in Heath
amps rated at 1/4th the power.
This seems to be the norm in amp design these days...caveat emptor!
(((73)))
Phil, K5PC
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