Mono Cartridge Question

If you read the OP you'll see that Miyajima was on my radar. I understand though, that it is a cartridge with no vertical compliance at all.

No dealer options available out here in the boonies!

The distributor has already replied to me on this Sunday night that he can give a discount for Black Friday. Evidently there is a massive markup he is willing to decrease somewhat. I have asked how much the discount would be.

I may be in error here, but my understanding is that mono cartridges on mono records tend to reproduce far less surface noise. If this is because surface noise results from vertical movements of the stylus, it makes sense as the vertical movements are ignored. IF any of that is true, there is then the complication that a cartridge for modern mono recordings must have some vertical compliance so as to avoid damage to a stereo record played inadvertently. This may be why I see some mono cartridges (eg from AT) labelled as dual moving coil cartridges. I assume the innards are the same as in stereo versions, but the coils are connected to sum the output to both channels. Now if we have the 45° arrangement of stereo coils, but wired to output mono, surely that just does the same job as a mono switch on the pre-amp?

Yes, I read the Ortofon page before. I was confused by this remark on the Cadenza MC Mono (one of the "True Mono" cartridges):

The coils are made from 6NX (99.9999 %) pure silver wire. An improved winding process on the armature allows a better channel balance.

"Coils"? Is it just lifted from the stereo Cadenza blurb, which has the same wording for the Red and Blue models? Or do they put two coils on the cantilever as usual but only have fixed magnets arranged to pick up lateral movement only? This isn't, or shouldn't, be complicated, but it is hard to find proper information.

This is good information. It's beginning to look like the question is whether a single coil (assuming that is how the Miyajima Zero works) is so much better than the 'neutered' stereo type like an AT33-Mono. The former is about six times more expensive.

Given my love of Decca cartridges, and a little knowledge of the way their coils are arranged around the armature, it seems to me it would be relatively simple to re-wire one so that only the coil responsible for lateral movement gets fed into both channels. I may have to ask about a mono conversion of my spare Jubilee.

Later: I just sent an enquiry to the new owner of the London Decca name, and CC’d it to John Wright as he is continuing to provide technical and training support.

No reply from the new owners of the London Decca name and business. Also enquired of Steve Leung (doesn't think it can be done) and Peter Ledermann (no reply yet).

Peter replied and I'm waiting for him to call for a discussion. I may be getting somewhere!

Chris

Well Peter said I'm crazy. Also a few things about Deccas in general "that I wouldn't say out loud in public." He's not a fan.

All I can do at this point is to hope that londondecca.com eventually get back to me.

Correct.

Hmm. There must be life at londondecca,com. The 'Service' button now opens a web message form rather than an e-mail link to service@londondecca.com.

So I filled it in. Also asked the old UK distributor at Presence Audio if he knows what's going on.

Isn’t that just the truth - we need some vertical compliance in case a stereo disk ends up under the wrong tonearm, but we don’t want any signal resulting from the vertical compliance to be fed up the chain.

Peter Ledermann did sort out something for me (honestly, he was very informative and able to answer some questions for me in ways that make sense, even if I strongly disagree with his opinions about Deccas). The issue of "true mono" pickups having dual coils: I assumed they were exactly like a stereo version, but the coils would be wired so as to send the combined output to both channels. Quite wrong, said he, and he should know. All the same components as a stereo version can be used, but the cantilever/magnets are mounted 45° away from the stereo version. Now it becomes possible to take the signal from the coil/magnet sensing horizontal movement and send it to both output pins. The other coil/magnet pair, that now senses vertical movement isn’t even connected. It shouldn’t even be there, but it is cheaper to make one cantilever with two coils on it, and presumably then mount the cantilever/magnets in the appropriate orientation for mono or stereo as desired.

This quiets my fears about pickups like an AT33 Mono or the Ortofon Cadenza Mono (both of which claim "true mono" status), which announce that they have dual coils etc. I’ll wait a week and see if either londondecca.com or Brian at Presence Audio give me a result. If not, I’ll have to choose between the AT and the Cadenza. The Ortofon is three times the price, but I do love it’s great uncle, the Kontrapunkt C. A Miyajima Zero would be twice the price of the Cadenza Mono, and I can’t justify that. I still think a mono conversion of the Jubilee should be child’s play for a tech used to Deccas, and would likely be better than any of the others. But, "You can’t always get what you want" etc...

Questions remain. VAS offer mono conversion of stereo cartridges. Do they just rewire them ("untrue mono"?) or do they rotate the innards such that one coil/magnet reads only lateral movement? I don’t know, but I wish these things were made plain for prospective customers. P. Ledermann says it isn’t worthwhile in terms of price to try to convert any of his pickups to mono, and one should buy one built as mono.

I find myself running out of patience with the new owners of the London Decca brand. Five weeks ago they promised to call their tech and ask if he knew how JW wired the cartridges for mono. Ten days ago I asked again if anything had been heard. Nothing since. So today:

Repeat send: still nothing? I don't want to be a pain. If the answer is no, please tell me and I'll run out and buy a mono cartridge.

 

Just let me know, and I'll still wish you well and be in touch next time my Reference or Jubilee needs a rebuild!

 

Chris

No mystery about it, if you use a mono cartridge with no vertical compliance you have to be careful to never set it on a stereo record. Or, you can use a stereo design made in a mono version (hopefully with the magnets mounted 45° away from usual as described above in my chat with Peter Ledermann, rather than simply strapped coils to sum both channels) and it will have the vertical compliance so that a mistake will do no harm. Those are the choices.

For those of challenged imagination, look at it this way: a groove wall with lateral deviations will push back against the stylus (yes, that's Newton's first law). The shape of the stylus will affect the direction of force exerted on the stylus, which just a little painless thought about vectors will make obvious. Image pushing your finger in a horizontal direction against a plane inclined at 45° to the vertical. Your force will be equally divided into a lateral and a vertical component, and the inclined plane will move not horizontally, but in a direction 45° above the horizontal. Those vectors will mean that a rounded stylus profile will experience not only lateral pushback, but also some in a vertical direction. That will tend to make the stylus go up and down, just like the chatter on a machine tool. A stylus with a side profile that is more vertical, will experience that force more in the lateral plane and less in the vertical.

None of this will matter more than it does with a stereo record and a stereo cartridge, as long as the mono cartridge has vertical compliance. If you have a mono cartridge that has no vertical compliance, all that vertical force has no suspension to damp it: it must make the whole stylus/cantilever/cartridge move up and down with the resulting hammering in the groove. This seems rather elementary.

Now you might argue this - but what does vertical chatter matter if the groove only contains lateral information? Sure, we can go there. Conical styli used to play mono records for many years in the days when mono cartridges never dreamed of having vertical compliance. Did those records suffer more damage than a mono disc with a non-vertically compliant cartridge? Than a similar cartridge with an elliptical profiled stylus? Or a stereo record with a stereo pickup? I don't know, but I can see the theoretical argument for why this should be so.

This does make me feel more likely to settle on a cartridge that is an adapted stereo design, with its guts rotated 45° and with a modern profiled stylus. That way I'll do no harm if I accidentally put a stereo record under that pickup, and I know I'm theoretically less likely to damage my original mono Parlophone Beatles.

@goofyfoot If I don’t hear back from the overly laid back guy at londondecca.com by the start of next week I shall be ordering an Ortofon Cadenza Mono, of which Ortofon write:

The Cadenza Mono model is made with a Nude Fine Line stylus and a cylindrical aluminium cantilever. The stylus radius is r/R 8/40 µm.

That should give me some vertical compliance and a more modern profile than a conical stylus.

I'm discovering more mono LPs all the time. I was lucky enough to inherit from a deceased surgical colleague a remarkably eclectic collection of several hundred LPs. No end of bizarre stuff, you know, nose flutes, Irish dance and suchlike. But half of it is early music and classics. Yesterday I cleaned a lot of mildew off a 1951 Furwangler/Bayreuth/Beethoven No.9 which sounded fantastic! Such treasures deserve a proper pickup, which is why I started this thread.

I have to say that one reason why I am drawn to the Cadenza Mono is my experience with the Kontrapunkt C (from Ortofon's 250th anniversary of JSB series), which has now become the Cadenza Bronze. I know the AT33 Mono would be a lot cheaper, but then I'd be wondering if I was missing something!

I just need the nice man at Acoustand to send me two tonearm pods and I'll be away. His 55 day build time runs out next week (no holidays, weekends and three weeks off at Christmas) so hopefully there'll be a very heavy package on its way soon.

Decision time today, as still no reply from londondecca.com. I e-mailed my enabler* and he is ordering me a Cadenza Mono and a Cadenza Bronze. I spent some time with the microscope today and it's plain the Kontrapunkt C has to go to the spa for a refresh - hence the Bronze).

*Jody Crane at brooklynaudioinc.com in Dartmouth, NS.