[R-390] R-392 audio improvement=super, can R-390 audio be improved?

[Frank Hughes]

Hi,
Some months ago C. Steinmetz kindly sent me a schematic and some notes for
a FET audio circuit for the R-392, replacing the 26A7.
Schematic says "S. Johnson, 6/6/91" so although I'm sure many already know
all about this, it was new to me.

Used current production FET "VISHAY IRF510".

The "FET-sicle" (Note the Popsicle stick) works GREAT.

http://i180.photobucket.com/albums/x257/fish1_07/R-392/DSC00004_zpsz46tzmo0.jpg
http://i180.photobucket.com/albums/x257/fish1_07/R-392/DSC00003_zpshjyjqe4g.jpg
http://i180.photobucket.com/albums/x257/fish1_07/R-392/DSC00002_zps5rfsedsw.jpg

Had an old Radio Shack "Optimus" bookshelf speaker, and one of the Hammond
transformers we typically use with the R-390, R-390A audio.
Sounds super on the R-392 w/ audio mod.

Is there any way to obtain a similar audio improvement for the R-390?

The R-390 I use for AM operating (w/ a 32V-2) sounds like crap via the rear
terminal block/Hammond transformer/Radio Shack Optimus.
Connecting some JRC headphones to the front panel jack of the R-390 sounds
better, so I know the good audio is in there somewhere.

Or I have messed up connections/jumpers on TB101-TB102?
http://i180.photobucket.com/albums/x257/fish1_07/R-390/DSC00005_zpsdb6vcztn.jpg
http://i180.photobucket.com/albums/x257/fish1_07/R-390/DSC00007_zpsnxbu1qdp.jpg

The R-390 audio circuit components appear to be the original 1951 items.
So possibly it is just time to refresh some aged components?

http://i180.photobucket.com/albums/x257/fish1_07/R-390/82b182cb-1467-4431-a5d8-87ef79073daf_zpsqy8uk2bd.png
http://i180.photobucket.com/albums/x257/fish1_07/R-390/01f1395a-ef0b-447e-b2b2-f31616fd983c_zpsgoylonyu.png
http://i180.photobucket.com/albums/x257/fish1_07/R-390/44e6b383-713c-419d-be37-fd66651a4ad4_zpskaw0t2rf.png
http://i180.photobucket.com/albums/x257/fish1_07/R-390/4160e6ae-7693-4cbb-b945-d197a108ce8f_zpsakrrugjm.png

73,
Frank
KJ4OLL