In response to my CES Report on Phono Stages, Atul Kanagat writes:
Having explored the impact of the assymetric application of EQ on records from Columbia, Blue Note, Verve, DG, Decca etc, I'd like to suggest to TAS that any phono stage that lacks a variety of EQ options should not be considered a serious audiophile product. The distortions created by the assymetric EQ are very significant and frequency dependant; most audiophiles have never really heard what's on the record for 30 to 70% of their record collections without proper EQ.
I responded with:
By your definition, very few phono stages would be considered serious audiophile products. My understanding is that in 1954, RIAA became the de facto industry standard. Prior to '54, each record company used its own equalization so there were literally over 100 combinations of boost and rolloff in use. A phonostage/preamp would have to account for all these combinations. However, the predominant ones were LP, FFRR, AES, and NAB.
So what happens if one doesn't have the correct bass boost and high frequency attenuation (on playback)? Nonlinear response in the bass and treble, and conceivably more "noise" in the form of hiss and clicks. Has that been your experience?
I don't know when the group of labels using Columbia EQ (CBS-Sony, Atlantic, Verve, Pablo, Reprise, etc.) and Decca EQ (Decca-UK, London, EMI, DG, Angel, L'oiseau-Lyre, etc.) actually adopted the defacto RIAA standard, do you? Presumably, those recordings after that date would all conform to the RIAA spec and not be problematic (at least for EQ reasons).
In any case, the Zanden Audio site has some interesting information about their RIAA, Decca (FFRR), and Columbia EQ options on their phono preamps. What other phono stages have these, and other, EQ options?
Anybody else want to weigh-in on this? Certainly a de facto standard didn't require compliance, and some companies, like Columbia and Decca may have continued down their own respective EQ paths for some time. Does anybody know how long?