[R-390] HSR-2 vs 390a

[Dan Merz]

Hi,  now I'm a relatively new guy on this reflector but I've gotten a
lot of good information out of the questions I've put on here - and I've
seen a lot of good information in the archives.  And I find the R390a I
have is the receiver I use most often,  pretty much standard except for
an audio improvement and substituting the 390 (non-a)  i.f. chassis.
So I'm putting a somewhat general query out based on a recent article I
read in Electric Radio,  Jan 2004 issue having to do with performance of
an apparently pretty simple homebrew receiver vs. R-390a.  Just for
information here,  the receiver consisted of 6be6 mxr, followed by 3
i.f.  6ba6 stages and 6bj6 det.  etc. with no rf tube in front of the
mxr,  just a couple of tuned circuits.  The full circuit is to come in a
future article.   What caught my attention was the statement -
"Comparison to my very well working 390a was dramatic,  I could CLEARLY
hear signals that were well under the hash level of the 390a, but very
comfortable copy on the homebrew receiver."  As best as I can tell,  the
radio is being used on 40 meters and frequencies below that and
primarily on AM.  I have in the past been made aware that rf stages in
front of the first mixer are not so necessary below 20 meters,  probably
first brought to my attention by the Squires-Sanders receivers and then
later by advanced transistor receivers in QST.  But what I'm wondering
about,  are there other factors that would make the 390a inferior in
certain cases to a simple receiver as expounded in this article?   Dan.