[R-390] R 390A Audio and AGC

[Perry Sandeen]

GM List,

No matter what brand of 600 ohm to 4/8 ohm transformer one uses, one still has the same original crapola sound.

There was an article titled Cheaper and Simpler Upgrades for the R-390A HF Receiver by Chuck Felton  KD0ZS (Felton Electronic Design PO Box 187 Wheatland, WY 82201 published in Electric Radio Magazine August 2004.

Among many improvements he covers are the factory audio problems.     

I have Chuck’s permission to redistribute his article.  If interested reply off list and I’ll email a copy.

There are some audio improvement mods to be found in the Y2KR3 manual also.

For a few dollars more (sorry Clint) for a P-P output transformer from antique audio, one can do the Kleronomos  mod.  This mod can be modified to use P-P 6AQ5 tubes mounted in place of the 8 pin plug in capacitors by using modern replacements mounted on a terminal strip underneath the large filter chokes.  Of course if one doe this one should remount the three power resistors underneath the chokes to the top side of the chassis.

I have a copy of that schematic also if one needs it.

Regards,

Perrier