Plug-in, self-contained product detector for the 51J series.

[Ed-VA3ES]

I just posted a detailed  informational link over on the Receivers forum:
http://amfone.net/Amforum/index.php?topic=24308.0

This link describes a fully self-contained, plug-in product detector for the 51J series.   Comes fully built up.   See more over at
http://amfone.net/Amforum/index.php?topic=24308.0
or  go to
http://www.treetopcircuits.com/pmwiki/pmwiki.php/Main/PD3

[sndtubes]

Just to throw my 2 cents in, I'm using one of these product detectors in my 51J-4 and it works very well.  Does the 51J-4 perform like a 75A-4.  NO.  But for a very simple, cheap and reversable mod, it's great.  This PD is a very worthwhile addition and vastly improves the CW/SSB performance of a 51J series receiver. 

My criticisim would be that  the 51J has a lot of background hiss and noise compared to the 75A4 when using it in the SSB mode.  My guess is that the problem lies in the mixer, not the product detector.  The only thing I'd like to see with this product detector is a fast/slow speed which as I understand it is complicated, so it's absence is not that big of a deal.


But in conclusion, TWO THUMBS UP FOR THIS PRODUCT!!

Mike WB0SND

[ke7trp]

I saw that on Fleabay. I was wondering how it worked.  I wish they would offer more of this type of kit for SP600 and R390 ect..

C

[w3jn]

My criticisim would be that  the 51J has a lot of background hiss and noise compared to the 75A4 when using it in the SSB mode.  My guess is that the problem lies in the mixer, not the product detector.  The only thing I'd like to see with this product detector is a fast/slow speed which as I understand it is complicated, so it's absence is not that big of a deal.


But in conclusion, TWO THUMBS UP FOR THIS PRODUCT!!

Mike WB0SND

Inadequate filtering of the output of the product detector, I'd bet.  Look for remaining 500 KC components at its output with a scope.

If you can live without an IF output jack, using the existing 1/2 12AU7 IF out cathode follower as a product detector is a very easy mod.  Almost all the work is done for you, just run BFO into it, add a few resistors and caps, and run audio up to the AM/CW switch (which requires dropping the front panel) to switch the audio.