R390A, the Best Receiver of the Tube Era
Purchased this at Dayton in 2013 for a very low cost of $150 due to a rainy day. I was able to repair the receiver in one day.
- To match the 600-ohm audio output to a modern 4-ohm speaker I used a 12V transformer.
- To prevent the GFCI outlet in my basement from tripping every time I plugged in the radio I had to bypass the OEM power entry module, using 0.01uF safety bypass caps across the line.
- I developed a scheme to transmit SSB with this radio by splitting the VFO output (which is fairly high power), feeding half of it to a VFO frequency converter. The output of this converter feeds directly to a 5 MHz VFO input on a 20m SSB radio that I developed. So now the R390A tunes my 20m SSB transmitter allowing me to transmit back to those stations I tune in on the R390A. An article on this will be published soon in QST hints and kinks.