6922 vs. 6DJ8 vs,7308

Umaasa:
Below are a number of sites that give the info you are looking for. Pretty self explanitory. Look at the first three sites under tube data for an hour or so. You will find them very helpful if your getting into tubes.

Section VI: Tube Numbering and Tube Data, Amp Schematics, Glossaries/Dictionaries.

Tube Numbering explained:
*) Tube Numbering Systems (from Frank’s site) http://home.wxs.nl/~frank.philipse/frank/tubnum.html
*) Philip, Valvo & Mullard Valve Coding: http://www.cs.helsinki.fi/u/oheinone/valves/pvm-coding.html
*) Tube Numbering (from MachMat Site) : http://www.machmat.com/info/index.htm
*) Russian encoding system: http://www.arrakis.es/~igapop/russianotes.htm

Tube data:
1) Duncan Amps: http://www.duncanamps.co.uk/cgi-bin/tdsl3.exe/searchform
2) Frank’s Tube Data Page http://frank.nostalgiaair.org/index.html
3) Triode Electronics Tube Data Sheets: www.triodeel.com/tubedata.htm
4) Radau5”s tube data sheets: http://www.radau5.ch/valves.html
5) Tubebuilder Tube Data: http://www.tubebuilder.com/tubedata.html
6) Vacuum Tube Valley: http://www.vacuumtube.com/FAQ.htm.
7) Svetlana, Tube Dictionary: http://www.svetlana.com/docs/dictionary.html
8) Audiomatica, Tube Directory: http://www.mclink.it/com/audiomatica/tubes/home.htm
9) National Valve Museum’s list of Equivalents: http://www.valve-museum.org/
10) 4Tubes. http://www.4tubes.com
11) Tube Collector’s Association: http://www.tubecollectors.org/
12) Mach-Mat: http://www.machmat.com/sheet/index.htm
13) Kytelabs Tube infobase: http://www.qsl.net/dl7avf/roehren/roehren.html#TOC
14) An Intro to NOS tubes: http://www.soundstage.com/tubeor/tube.htm
15) Western Electric Archives: http://www.westernelectric.com/spec_sheets/we_spec_sheets.htm
16) Tom Jennings: http://www.wps.com/archives/tube-datasheets/index.html
17) Åke’s TubeData: http://www.tubedata.com/

I remain,

They are all Interchangable. I have found the 7308 to be a nice upgrade over 6922.

A simple, brief answer - yes, they are all interchangeable with absolutely no problems. Again, to be brief, the pecking order is 6DJ8, 6922, 7308 i.e. good, better, best.

Now is you want to find out which is the best brand of the above noted variants, that is a very complex and very opinionated question in which we will need to know more about your system set-up, application, and sonic objective.

Nobody with moniker "Clueless" can post a list like that. That's it--I'm having A-gon revoke your moniker--it's just not working.