Siemens 6922 tubes?

[maxhifi]

Here's a photo of one, there's five of these and probably 3 more mundane brands RCA and sylvania

 

[maxhifi]

And here is the preamp circuit I Am considering

 

[primosounds]

I picked up 16 Amperex USN-CEP 6922s & 7308s from a military surplus auction about 12-15 years ago. They are excellent. Purchased them for $7/ea. Later sold off 8 of them for $65 each. I ended up with 8 great tubes and $400 profit.

Some years ago i had the pleasure of meeting this old school ham radio guy who used to have a business with military surplus, who liked electronics and he would get all this stuff from government auction. He stripped out the tubes from equipment and saved the ones he wanted. But in a 55 gallon drum he had the "rejects" . And one day i looked in the barrel because i could see some gold pins flashing in the light. And what those tubes were mostly thousands of 6922 and 7308 amperex with the green labels and white labels. I moved some equipment for him and he let me have as many as of those Amperex's as i wanted. Unfortunately, this was before i obtained my 6dj8 based equipment and totally addicted to tubes so i just took 2 pocketfuls of the best looking ones. A few years later he gave up his business as he was getting too old and now somewhere in the local landfill there is a 55 gallon drum full of Amperex 6922 and 7308 tubes.