[Amps] Designing the Cleanest Linear with RF Negative Feedback

[Tom Cathey]

> They also say that IM product do not necessarily drop as drive is
> reduced. It can actually be greater at lower power levels than at higher
> power levels. IM products drop way down at one point midway in the power
> range and then go back up again. They show a graph that is derived
> mathematically and say that most tubes follow the graph pretty closely
> to the predicted IM performance ratios of drive to bias amount.
>

Gary,

Yes, I've read that too, but then I've read the opposite.. That statement 
above would make my question about using a chain of GG tubes running at 
1/10th reduced ratings a poor idea. I'm a little confused cuz I see it 
written sometimes that for very linear operation, sometimes stages run at 
1/10th  their power ratings in class A.  Maybe that's for special purpose 
receiver high performance preamps or something like that.

Anyone else for comments?

T