They are all Interchangable. I have found the 7308 to be a nice upgrade over 6922.
12 responses Add your response
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.
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 FrankÂs 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
1) Duncan Amps: http://www.duncanamps.co.uk/cgi-bin/tdsl3.exe/searchform
2) FrankÂs Tube Data Page http://frank.nostalgiaair.org/index.html
3) Triode Electronics Tube Data Sheets: www.triodeel.com/tubedata.htm
4) Radau5Âs 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 MuseumÂs list of Equivalents: http://www.valve-museum.org/
10) 4Tubes. http://www.4tubes.com
11) Tube CollectorÂs 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) Ã keÂs TubeData: http://www.tubedata.com/
Hey thanks. It's part of a larger "guide" to online DIY tube info I have put together. If you find that list helpful you might find some of the rest helpful. Drop me an e-mail (You cant' send attachments thru Audiogon email system)with your address and I'll send ya the rest. It's convenient because it's a word doc with live links.
I would caution against the over reliance on any "pecking-order" with respect to "good-better-best" with these tubes. Aside from synergy with particular components, there is variability between brands and even between types within brands. For instance, I had a set of military-grade Telefunken 6dj8's that were much sweeter and less microphonic than MANY of the 7308's, 6922's, and Cca's that I also tried. Also, don't let anyone fool you into thinking that all gold-pins are better than all steel pins.