6922 is an industrial number for 6DJ8 with specific performance requirements to be so designated. 7308 is an even better version of the same tube. Amerex PQ ( premium quality ) 7308's had gold plated pins. These Amperex PQ 7308's are my favorites. A little detective work may yield good results in finding some excellent 6DJ8's. Try to find some New Old Stock (NOS) examples. Best of luck in your quest.
Tube advice
I'm thinking about replacing the tubes in my x-10d (Musical Fidelity). Now I know nothing about tubes-I believe the type used is Philips 6922's-I got this from another news group.2 questions. 1.Does it have to be exactly the same serial number or is there a generic form which this number relates to and therefore others I can use? 2.Obviously I'm thinking about changing with more expensive tubes-I'd seen Telefunken mentioned-is it possible to make a major mistake with the more cash is better theory? I appreciate there may be a degree of subjectivity involved in the latter question. Any help appreciatted and thanks in advance, Ben