The problem with old records is not only RI.A.A. but in many cases also reverse/inverse phase:
"those made in the late 70's & 80's, many labels did not adopt R.I.A.A. curve in the 50's, 60's, 70's and even 80's, that was why even though I had acquired many LPs, half of them did not sound good. Yamada-san further explained to me several years ago in the tube era, big labels such as DECCA, EMI, Deustche Gramophone used their own in-house equalization curve in their recordings and all of them were in reverse/inverse phase, you can easily check this out when you play CDs with old recordings of the abovementioned labels"
"those made in the late 70's & 80's, many labels did not adopt R.I.A.A. curve in the 50's, 60's, 70's and even 80's, that was why even though I had acquired many LPs, half of them did not sound good. Yamada-san further explained to me several years ago in the tube era, big labels such as DECCA, EMI, Deustche Gramophone used their own in-house equalization curve in their recordings and all of them were in reverse/inverse phase, you can easily check this out when you play CDs with old recordings of the abovementioned labels"