I’m about to purchase some NOS Siemens 6922 tubes (a trio) for a Conrad Johnson Classic 120. I have been using NOS Amperex 6922 tubes, which are fantastic. But I want to have several NOS back up sets of tubes, so I am going to give the Siemens a go.
I’ll report back on how they compare to the Amperex 6922, but this won’t be until sometime in January.