6DJ8 vs. 6922?

are 6DJ8 and 6922 tubes inter-changeable

yes in all cases

the question of preferences is very long to answer, and highly dependent on what gear the tube(s) are being used in and what sonic profile is sought - different circuits and applications have very different sensitivities to the specific make/type of 6dj8 used

in general, excellent 6dj8 variants are old stock usa or european made ones from rca/amperex/philips/mullard, though very good quiet ones, especially matched sets, are getting expensive

more cost effective options are old stocks from japan and eastern europe (hungarian tungsrams , yugo made ei's, czech made teslas)

agree w @rodman99999

no misinformation posted here that i see on the op’s basic query

i have probably ~1000 pcs of 6dj8 variants i have collected over the years, from european cca’s, ecc288/188, 7dj8/pcc88, bugle boys, a-frames, tele’s, adzams, mazdas, cifte’s, russian rocket 6h23p’s and so on... reason being i have been a c-j preamp user since the 90’s, and for many years, my beloved premier 16ls2 used 6 at a time

folks who have answered here to the op like myself and rodman999 have a substantial experience base with this tube (and tubes in general)

that said, i don’t know why one commenter went on about 12au7 5814 etc etc... got nothing to do with a 6dj8 except the physical tube form

from brent jesse audiotubes website:

6922:

This is one of two premium versions of the 6DJ8 tube. First of all, it is the same tube as the 6DJ8, and will work wherever a 6DJ8 is needed. It has premium features such as low noise, low microphonics, and usually a longer lifespan....Most are factory screened for tight internal matching and low noise.

here is the whole page... if you really want to understand this topic thoroughly, especially regarding ALL the variants, read ALL of what is written here  ...http://www.audiotubes.com/6dj8.htm

separately, these past detailed a-gon discussions may be helpful to those new to this party, or needing reminding of the knowledge base that many of us have benefitted from

https://forum.audiogon.com/discussions/tube-characterization-6dj8-6922-7308-cca-etc

https://forum.audiogon.com/discussions/tube-characterization-6dj8-6922-7308-part-ii

Strangely enough many ECC88 sound better with more air and musicality compared to their bigger cousins like E88CC and E188CC.

i have found this to be true sometimes as well

experienced tube rollers understand that with small signal tubes, sometimes a small amount of sympathetic ringing/microphonics can add a positive character to the sound -- more air, more reverb, more depth to the soundstage - whereas a highly ruggedized military spec tube with dual or extra triple mica supports etc etc can sound ’dead’ in comparison

i have always liked the 60’s amperex bugle boys with ring getter (not a-frame) for that reason, in many cases they provide the ’goldilocks’ sound