> before applying all of the RIAA playback EQ
Same thing. You know but I'll mention: most of the slant in the RIAA curve is not to make the RIAA happy, it is because the dynamic needle integrates EDIT differentiates groove position and causes a 6dB/oct rise. You can take it or leave it; you can convert one to the other trivially. Yes, in the 1980s it could have been much simpler hardware to do some processing before the integration.
I submit though, that for running through Grandma's stash, he will be fine with any 78 table, a blunt needle, an RIAA preamp, and a TREBLE knob. There's real treble on many 78s, but surface noise can be offensive to modern ears (specially on modern tweeters).
A steep 6KC/3KC low-pass is handy to cut the noise while leaving some music. 6KC cut is utterly defensible because few players of the time even got that far. Some late 78s have >6KHZ in the groove, but it may have never been heard by artist/producer, so its "authenticity" is debatable. If it sounds good, do it; if it sounds bad you should remove it.
> old 78's are all over the place for EQ
True but... whatever graphs the Tech Dept put out, the music in the groove was always made to sound terrific on the players of the day. While in theory a company which sold records and players could optimize one for the other, they could not let their records or players sound like junk when used with competing players or records. So producers pushed the band around to get a tonal balance which worked in the end.
And players never had "EQ knobs", and the tone control was not intended to correct minor EQ errors. In a given era(*), an "average" EQ will give pleasing reproduction.
(*)There are significant differences in practice between early acoustic recording and late electric recording, but acoustic and electric players were both used for considerable time so change was gradual, mostly in extension of bass/treble control beyond what you got from a mica diaphragm in a morning-glory horn.
