I have a few fresh master tapes.
I made them using different current production tape formulas (some ATR, some RTM).
They're <1 year old.
Mastered from
what?
Your own source material, I presume -- that's the only way they can be first generation.
Copies of digital recordings don't
really count.
Of course you can have a freshly-made master tape. What you cannot have is a "fresh master" of, say, the original, assembled mix of
Abbey Road. You could
copy the master or
make a new master from the original multi-track tapes, but the master is/was "one and done". There can be multiple first generation copies (multiple masters, "A" and "B" masters) made at the same time, but they're contemporaries. If they were made 40 years ago, it's hard to say one is "fresh" unless this is meant to mean "never played" (which could be possible).
I inferred the earlier reference to "fresh masters" was for new re-pressings of (more or less) vintage materials.
So... tapes.
Every commercial recording (from the tape era) should stem from one master tape.
There is the master tape, made from the final, assembled mix of the album. This is the first generation.
There are safety backups, which are usually, perhaps always, copies of the master (series, not parallel), so second generation. These may or may not have seen use in generation of stampers for pressing records. Either way, they're not the master.
There are early generation(second, third, maybe fourth) tapes which are (were) typically what go out to the pressing plants -- especially "abroad"
and/or for popular recordings (i.e., those pressed in large numbers at multiple plants). The cool guys snag these "early generation" copies when they can find 'em -- they are not inexpensive.
The master is safely stored away for later money-making opportunities and/or to be destroyed in archive fires.
...and, obviously, some folks go in and make
new mixes and
remasters and all that malarky.
This thread looks like a reasonable discussion; note particularly SH's interjection @ post #7
https://forums.stevehoffman.tv/threads/first-generation-master-tapes-what-are-they.204613/