[R-390] R-390 vs R-392?

[James A. (Andy) Moorer]

Wow! Ask a question, get an exquisite dissertation! I noticed the range 
problems with the AGC and strong signal behavior, but missed a lot of 
the subtlety. I didn't bother to spend any time on the audio and AF
side after  declaring it a train wreck. thanks for digging into it so 
thoroughly.

Thanks for your most complete and informative study.
May I post your missive on my web site? (with attribution)

--A

On 3/3/2026 17:43, Mike Peace wrote:
> Hi Andy,
>
> Here's the technical analysis comparison between the R390 and R392, 
> see link:
>
> https://vk6ada.com.au/wp-content/uploads/2026/03/R390_vs_R392_Technical_Analysis.pdf
>
> Mike
> VK6ADA
>
> On Tue, Mar 3, 2026 at 4:16 PM James A. (Andy) Moorer 
> <jamminpower at earthlink.net> wrote:
>
>     Has anybody done a comparison between the R-390 and R-392
>     performance? I
>     know the 392 is de-featured (one audio output, fewer BW choices), but
>     has anyone just compared apples to apples? That is, set the 390
>     and the
>     392 to the same station, using the same antenna, same settings? I
>     have
>     gone over the schematics pretty carefully and I don't see any
>     difference
>     in the core signal handling. The 26A6 tubes have perfectly reasonable
>     behavior and have equivalent bias, screen grid, noise figure, and
>     so on.
>     So, do they sound any different?
>
>     I noticed two other things - the IF output for the 392 is a wreck.
>     Seems
>     to be half-wave rectified. Lot of nonlinearity there. And the audio
>     output stage is quite different from the 390. That all-important IF
>     stage appears to be identical to the 390.
>
>     So - what's the story?
>
>     -A
>
>     -- 
>     James A. (Andy) Moorer
>     www.jamminpower.org <http://www.jamminpower.org>
>
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-- 
James A. (Andy) Moorer
www.jamminpower.org