10-09-2011, 05:43 AM
deckeda wrote:
The only way it wouldn't be setup with RIAA eq on the phono input is if it were only made to play 78s; RIAA was already the standard for LPs and 45s. It's 78s which had a plethora of non-standard eq curves. But if it sounds good, it is good.
RIAA eq. was standardized in 1954, but not all manufacturers adopted it right away. There were a number of competing equalizations as LP's had been introduced in 1948. Preamps for years afterwards might provide for switching between several of the equalizations. So it is quite possible the amp has something other than RIAA eq.