Thanks, Frank, for the link. Sad.

The R390A/URR Ultimate Performance, General Coverage AM & CW Receiver

It works fine for SSB, too. In 1960, during a sea trial on the USS Little Rock
as a Philco Tech Rep, I used one to run phone patches. The rig was a 1500 watt
TMC vfo phasing rig. (It had an 8 Hz frequency variation due to the vibration
on the variable capacitor caused by a bent propeller shaft. LOL)

I had such great luck with the stock R390A (in the main transmitter room) and
the Navy guys in Radio Central were having so much trouble with the TMC ssb
adapters they had down there, they started using the 390's without the adapters
as I suggested. G

Bill, K5BY