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Is RIAA equalisation enough for Phono Stages?

This question was bought up in the latest HiFi+. In particular, the editors report back from the Dem he put on at the Rocky Montain show. To summarise the argument, he says that even after all companies signed up to use RIAA in the 70's I believe, in fact they did'nt. The poor results from DGG in particular, with screetchy, painful treble, is all due to this. Played with the proper correction, they are transformed.
Now a number of stages, both cheap and expensive, provide alternative equalisation, but not all, including many expensive ones. I believe Graham Slee at the cheaper end, EAR, Manley Steelhead, Zanden, all do, for example. Should it be a more important considerration in choosing a stage? Looking at discussions on this site for example, it does not seem to come up much.
david12
piedpiper
753 posts
 
It appears that some definitive research is in order as to what different curves would be appropriate for the different eras of the different companies.
tbg
5,263 posts
 
EMT had a phono stage at the last CES with many choices on equalization of records. One listen to it suggests that you need more than RIAA. It also works for 78s.
rgordonpf
82 posts
 
This site http://geocities.com/midimagic@sbcglobal.net/mixphono.htm has an expalnation of Pre RIAA equalization. If you click on the "Recording curves" and "Record label usages" links at the bottom of the page you will see the various Pre RIAA curves.

Since I have many pre 1955 LPs, I have researched Pre RIAA EQ fairly extensively. I have seen numerous mentions that some Record Labels, particularly European labels, did not switch to RIAA EQ when the standards were adopted in 1954. Some of the articles that I have read say that most, but not all Record Labels had adopted RIAA by the end of the '50s. Some labels, however, did not switch to RIAA until the early '60s (European Decca!). The Record Usage Label table at the above website shows a number of record labels that did not switch to RIAA until much later than 1954. Though that table is not complete. I have a 1960 mono Philips LP that has the treble rolled off at the Pre RIAA slope of 6dB.

As you can see from looking at the EQ tables at the above mentioned website, designing a phono stage that can properly EQ pre RIAA LPs is a complicated task. If you are only concerned about 33 1/3rd LPs, then you need four different setting for restoring the rumble shelf, you need five different settings for bass rolloff frequency, and you need seven different settings for the slope of the treble rolloff. To have this many settings and audiophile quality sound is not a trivial task and it does not come cheap. I have been working with one manufacturer in helping him determine the settings for the Pre RIAA phono stage that he is designing. We have had lengthy discussions regarding the need versus the cost and effort required to add each separate setting.

An audiophile quality phono stage that can handle any Pre RIAA 33 1/3rd LPs is not going to be cheap.
tbg
5,263 posts
 
Rgordonpf, and the EMT is not cheap!
patrickamory
193 posts
 
The EMT JPA-66 looks absolutely gorgeous. I love their arm and cartridges and would love to hear it.

On a cheaper note, I've got the Sentec EQ-10 tube phonostage coming from the same (US) distributor. It's made in Sweden and allows many variations for mono LPs (and now, it appears, some stereo LPs!) and 78s.

http://www.toneimports.com/sentec/sentec_eq10.html
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