Mono cartridge classification

Thanks, Pryso. Your understanding of which styli to use for which recording era matches mine. Perhaps I got it from you! Have you checked out the Esoteric link I posted above? There's some pretty good info there that seems to match yours (and it's pretty clear, too!).

I'm confused enough about mono, so I'm scared to even think about 78s!

Not to open another can of worms, but do you use any kind of equipment to match the pre-RIAA EQ curves (Esoteric Re-Equalizer, KAB Souvenir, etc.)? I just use the tone controls on my integrated amp, at least for now. Works pretty well.

-Bob

Oooh, boy. This is a pretty complex area you're getting into. Google will be your friend. The wide range of contradictory information you find will be your enemy. I'm just learning about the world of mono myself, so take everything I say with a grain of salt. And I hope those more knowledgeable will double-check me. But here goes:

That symbol you're talking about is almost certainly the symbol for micron (also called a micrometer). The thing to remember is that 25.4 microns equal 1 mil. Generally, you will see today's typical elliptical stylus dimensions stated as .3 mil x .7 mil. These serve well for playing mono records. When you see a stylus specified in microns, just convert it.

Despite the fact that I said a .3 mil x .7 mil stylus is fine for mono records, many people maintain that it is best to use styli that are similar to those used at the time the recording was made. VERY GENERALLY speaking, records that are not labeled either "mono" or "stereo" are mono recordings. These, according to some, should generally be played with spherical (aka conical) styli of 1 mil (25.4 microns). If the record is labeled "mono," it was probably made during the early stereo era. Since the record grooves were narrowed at this time, it's GENERALLY best to play these records with spherical styli of .7 mil.

Modern high-end cartridge makers like Lyra are today making very expensive mono carts and maintain that variations of modern fine-line styli are best for playing mono records.

Also be aware that cartridges that are sold as mono carts actually do produce a mono signal (Denon DL-102, Grados). But some are called mono only because they have a bigger spherical/conical stylus appropriate for mono recordings——BUT their output is stereo (Ortofon D25M, I think). The signal must be summed by a mono switch on a preamp, by wiring the cart for mono, or by using a double-Y connector to sum the signals.

Keep in mind that in discussions of mono, the term "LP" is used to refer to 33-1/3 RPM records, as distinct from 78 RPM.

If this isn't confusing enough for you, I invite you to hit Google. A very good summary is offered here:

http://www.esotericsound.com/CartStyli.htm

There's also a mono forum at Lenco Heaven:

http://www.lencoheaven.net/forum/index.php?board=18.0

Hope this helps, but I'm guessing it might not!
-Bob

Sorry. The first sentence of my fourth paragraph, above, should read:

"Also be aware that SOME cartridges that are sold as mono carts actually do produce a mono signal (Denon DL-102, Grados)."

-Bob

Thanks for checking me, Pryso. I need it! Still learning.

Here is a post by Jonathan Carr of Lyra that says Lyra listened to a wide range of mono recordings in developing their stylus. He says the records were both pristine and well-worn, but he doesn't cite the eras they represented. I assumed that by well-worn, he meant they listened to records from many eras, but he doesn't explicitly say that:

http://www.audioasylum.com/cgi/t.mpl?f=vinyl&m=418745

About Grado, I was careful to say that they produce a mono signal. As you said, I believe they are "mono carts" in that they are strapped to sum the L and R signals. Like you, I believe I've read that they do have vertical compliance, but I can't be sure. So they probably can't be considered TRUE mono carts like the Denon DL-102.

For your last question, the KAB website states that the KAB/Ortofon OM-1M is a stereo cart with a 1.1 mil stylus for mono playback. I believe this cart is the same as or similar to the Ortofon OM D25M, but I may be wrong about that. Do you know for sure?

I wish I had time to track down and post all the references I've drawn from——but I don't. So I hope others like you will continue to fact-check me. Not that we'll ever solve all the contradictions of mono! THANKS.
-Bob

Thanks so much for the information, Jonathan. Glad we're no longer talking behind your back! I'm glad you cleared up the question on which types of records you used in developing your stylus shape. I've certainly never heard of anyone doing such extensive comparisons of stylus shapes with mono records, so your findings are especially valuable.

Am I correct in understanding that you now use that stylus shape on ALL your cartridges, both stereo and mono?

I hope we haven't scared off our original poster, but I fear we have!

-Bob

Thanks a lot Ldorio.

So the Ortofon OM D25M puts our a stereo signal, right?

-Bob