Wow! That is an old beasty!
I used to work on the old Collins R390A and Collins actually still supports their stuff but some of the unique tubes are long gone, except what you can find at garage sales.
Old, but sweet. She's been in the family for a while. I am hearing impaired, managed to pass the 13WPM code test anyway, and the old Drake was my preferred receiver. I had heck trying to pull signals out of the Alinco DX-70, and it's finals crapped out later anyway.
Sweet sound and good control with the Drake transmitter and receiver.
It is a little tougher to set up.
/johnny