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

[Mike Peace]

Hi James,
Yes, I'm delighted you want to share my post and welcome your feedback.
I've created a Boatanchors Legend tribute section on my website and
featured you.
Please review this post and let me know if I should make any revisions:
https://vk6ada.com.au/james-a-moorer/
Cheers,
Mike Peace
VK6ADA


On Wed, Mar 4, 2026 at 8:55 PM James A. (Andy) Moorer <
jamminpower at earthlink.net> wrote:

> 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
>>
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>
> --
> James A. (Andy) Moorerwww.jamminpower.org
>
>