[Amps] TL922A and AL80A

[Tom Rauch]

> In working on the AL80A, I got a manual where I found out about the 400mA
IP
> limit.  I am certain that I was running the other AL80A much higher than
> that.  While the amp did not malfunction, I was concerned about the
quality
> of my signal. Hence my question about the limits.  If 400 mA is the real
> advisable limit for signal quality with one 3-500, then the TL922 is
> probably the better choice.  If the TL922 can be run in CW mode in the SSB
> position (several have told me that they do this all of the time) then the
> TL922 is definitely a better choice than the AL80A as a backup and there
is
> no point carrying amps down and back.

The AL80's have a good reputation, are reliable, and are definately not
"splatter boxes" even when pushed a bit beyond ratings.

The "400mA limit" is not a point where suddenly you will have major
splatter. It is the SLOPE of the operating load-line that determines the
production of harmful IM products, not the fact a line starts to change into
a curve.

You can find this discussed in Care and Feeding of Power Grid Tubes by
Varian, as well as discussions of IVS (intemittent voice service) operation.

73 Tom