Separate Phono Pre - $$ before I will hear a SIGNIFICANT difference vs. integrated?

I believe, in the context of either separate or integrated, my comments were 'true enough'.

wiki

Ultimately the New Orthophonic curve was disclosed in a publication by R. C. Moyer of RCA Victor in 1953.[6] He traced RCA Victor characteristics back to the Western Electric "rubber line" recorder in 1925 up to the early 1950s laying claim to long-held recording practices and reasons for major changes in the intervening years. The RCA Victor New Orthophonic curve was within the tolerances for the NAB/NARTB, Columbia LP, and AES curves. It eventually became the technical predecessor to the RIAA curve.

Between 1953 and 1956 (before the stereo LP in 1958) several standards bodies around the world adopted the same playback curve—identical to the RCA Victor New Orthophonic curve—which became standard throughout the national and international record markets.[7] However, although these standards were all identical, no universal name was used. One of the standard was called simply "RIAA", and it is likely that this name was eventually adopted because it was memorable.

It is possible that some niche record cutters were still using EQ curves other than the RIAA well into the 1970s. As a result, some audio manufacturers today produce Phono Equalizers with selectable EQ curves, including options for Columbia, Decca, CCIR, and TELDEC's Direct Metal Mastering.

OP

You would love the center control panel of the Fisher President II Console I inherited.

http://www.fisherconsoles.com/President%20II.html

In one drawer was a Garrard Record Changer, a couple of headshells, and a switch for Ceramic/Magnetic.

Other Drawer a Viking 75 Stereo Tape Deck. A switch for both types of tapes: Staggered or Stacked (In-Line). Staggered came first, a second mono head was added, about 1-1/4" away, upside down, for 2 track stereo tapes. In-Line was a single 2 track head like today.

It was made in 1958, Tape was Stereo, FM was not yet Stereo, LP went Stereo in 1958. Fisher came to my uncle's apartment and added a Multiplex Decoder on site for Armstrong's FM Stereo.

Selector Knob: AM; FM; Stereo Radio (Live Binaural Broadcasts); AES; RIAA; LP; NAB; 78; Tape; Stereo Tape

Radio had a brief Live Binaural Broadcast period, it was set up for that:
Selector: AM, tune it's AM tuner to NBC AM (live mic left side of stage). Selector: FM. Tune it's FM tuner to NBC FM (live mic right side of the stage) Selector: move to Stereo Radio. (I'm guessing which was left and which was right).

My current speakers are the horns, crossovers, and 15" woofers pulled from that console, in my new enclosure. Woofers re-coned twice, 1 set spare drivers downstairs.

Oh yeah, the 80AZ mono block tube amps are still kicking too.

https://www.google.com/search?q=fisher+80az&tbm=isch&source=iu&ictx=1&fir=DQH3F7O4r2nnxM%253A%252CPtqoclGrGT_fPM%252C_&vet=1&usg=AI4_-kSwTppSgh6H7NuVVz__Qvqqdy_xGw&sa=X&ved=2ahUKEwi0n-ypmenjAhViU98KHU65A14Q9QEwAnoECAcQBg#imgrc=DQH3F7O4r2nnxM:

Well, if you think you might want to upgrade your vinyl system, via cartridge or phonostage, then I would start with the Mani and a line level integrated. You can test the value of the Mani over the phonostage within the NAD receiver prior to purchase of a new amp.

Depends on what music you listen to. Does most for jazz .