David wrote:

The front end (tracking preselector, RF amp, Mixer) makes abig
difference. As does the absolute silence of the circuitry.

Still, no one mentions where the tubes come into play...
All the above could apply to my old drake R4...Except I
disagree about the absolute silence of the circuitry...
Nothing is absolutely quiet...
The front end (tracking preselector, RF amp, Mixer) of my
kenwood TS-830 is very good, and it has no tubes...
Are you telling me it would be better if I converted those
circuits to tubes? Sorry, I just don't buy it...
The R-390 is a great receiver because it was a *very* expensive,
carefully designed radio made for commercial/lab and gov use.
Not because it has tubes. I can list a whole slew of other
all tube models that are fairly pathetic in performance
compared to the collins.
Why didn't the use of tubes help those models?
MK