Is RIAA equalisation enough for Phono Stages?

ELdartford,

It is not a matter of "conveniently forgetting about the RIAA process." In a high resolution system, additional equalization circuitry, or any other ancillary circuitry for that matter, will definitely represent a degradation. Whether whatever benefit is gained is worth that degradation is a matter of priorities. It seems to me that if one is concerned about the issue, having it built into the phono stage as an alternate routing to the RIAA standard circuit is far superior sonically to having additional EQ either built in or, worse yet, outboard, where it would necessitate another pair of interconnects. If you find yourself getting impatient with this sort of thinking, then by all means, forgo on the finer points of quality in deference to convenience and tonal control.

BTW, I have never found the noise on reel to reel or that of a quality vinyl playback system, assuming high quality records, to be worth the degradation of either DBX or Dolby.

Piedpiper...I agree that unnecessary equalization is a bad idea. Along those lines, I have experimented with a biamplified phono preamp. We (RIAA) go to the trouble of boosting the low frequencies, and then we use a crossover network in our speaker that cuts the lows back down for the signal going to the mid/tweeter. I found that feeding the tweeter with the raw (no RIAA) signal with just a passive filter to roll off the boosted highs gave remarkable clarity. Of course the woofer needs the usual RIAA LF boost. For this approach to work the design of the preamp and the speaker needs to be coordinated, and some provision needs to be made for signals that are flat, Tuner, CD, etc. A good DIY project, but not suitable for the mass market.

As for the tape hiss on pre-Dolby master recordings, you don't need a "high resolution" system for this to be evident, and, IMHO, annoying.

cool idea, for, as you say, DYI.

re: tape hiss: agreed, but a high rez system does help you hear what you're missing, hiss be damned, by using noise reduction. It's possible that listening habits, in terms of volume, may contribute to how annoying hiss ends up being; just a thought. Of course, what gets on one's nerves is very subjective.

If you have many records from 1960 or earlier especially earlier than 1955 on a variety of labels, it would definitely be useful to have alternate EQ options built into the phono preamplification. You could also use the variable options to tweak modern recordings but there might be better ways to do this -- I am not sure. The above poster who cautions us not to confuse phono equalization with what you can do with a good graphic or parametric equalizer makes a good point. Just as you want to approximate the cutting head with your VTA and shape of your stylus, you want to match the phono equalization to what was used when the record was cut. This is separate from how the record/master tape was mixed -- where I'd think a house sound or the mark of a particular recording engineer is created mainly.

It would be interesting to know if any labels did not really standardize on RIAA even though it is so stated on the records and covers. The specific equipment and components used would also contribute to some variation but nothing like what happened during the 78 rpm era -- where tolerances on resisters and such were so much wider than they are today -- or so I have read from folks in the 78-L and ARSCLIST. I have not read the article in HIFI+ but would love to see it if anyone can email me a jpg or pdf.

I just got a Reequalizer unit from Esoteric Sound for 78 and early LP playback and transfer and it is easy to use and does not introduce any obvious noise that I can hear on my system. Going forward, I also hope to try out a phono stage with variable equalization built in. The manual for the Re-equalizer is available for download at www.esotericsound.com and explains the issues of phono eq v. clearly.

Since I have been researching phono stages with variable EQ, I wanted to mention some units which have it in addition to Graham Slee's Jazz Club and Revelation.

Hagerman Bugle Pro around $400, Hagerman Archiver balanced design $999, KAB USA Souvenir around $1200, Eldberg MD 12 MkII around $1200, Millennia LPE-2 $10k, FM Acoustics 222MKIII 18K, and others I am sure.

I know that SimAudio's latest unit has 1 alternate EQ setting for earlier LPs.

This is a specialized product and none of the fully variable eq phono stages are carried by a local dealer. You have to commit to some costs in order to check any of these out. I would love to know others experiences with any variable EQ phono stages. Best, Stephanie