Why choose LOMC cartridges?

[luckydog]

Lini, ETM.........personally, caveats as to interpretation apply !

AFAIK certain published ETM figures might be determined by measuring 'top resonance'. Modelling as spring-mass where spring=vinyl elasticity and mass= inertia at stylus tip (ETM). Assuming cantilever rigid and behaves as a single body including the armature. I really doubt this model. I prefer that the top resonance is about cantilever flex and transverse cantilever vibration, part of which involves armature inertia loading - and this would render the common model of ETM fairly meaningless IMO.

On the face of it though, published ETM specs apparently can simply sometimes be a restatement of 'top resonance', which AFAIK are broadly similar between LOMC and MM, at least for the better examples. IIRC Miller Audio publishes fr measurements of both better LOMC and MM examples, from which top resonance can be derived.

Just my own 2p worth, as ever - glad you like the icon, lini awprint:

 

[lini]

ld: Yup, I'd also rather suggest to take tip mass specs with a grain of salt - also because it's often not quite clear whether it actually is equivalent tip mass or rather just the mass of the diamond... Nevertheless I'd consider Flavios list as good enough to consider the "lower moving mass myth" as busted.

Greetings from Munich!

Manfred / lini

 

[dlaloum]

Mr. Pig: I think it was Flavio in his advanced stylus shape thread over on VE, who compiled a list of lowest ETM specs... Let's see... Yup, on page 12 of 22.

Greetings from Munich!

Manfred / lini

Flavio's list was derived from manufacturer specs.... The specs were sometimes published in user manuals sometimes in brochures.

Ortofon quoted ETM on all their cartridges until quite recently (last 5 years)

A couple of years back I read up on the method of calculating ETM (which as LD says is an equivalent for the cantilever resonance) - and then verified the calculation method by measuring every Ortofon cartridge I could get my hands on (whether MI, or MC) - The results were consistent with the specs...

I then used the same method to compare with other cartridges that I have for which the ETM is not quoted.

As LD states, there are some assumptions in this "industry accepted" method of ETM measurement - and it may not in fact be measuring the true "effective tip mass". (although it is sure to be closely related)
LD is the physicist not me!
But as a relatively easy standard means of determining how light or heavy a particular cartridges moving components are, it is without compare.

With regards to the ongoing debate about LOMC being lower mass than MM, I have several MM examples that measure out as lower mass than recent model Ortofon LOMC's.... (see the 2006 Ortofon cartridges brochure)

Some examples:

Ortofon MC Rondo Bronze = 0.3mg
Ortofon MC Samba = 0.5mg
Ortofon X5-MC (early version) = 0.4mg (HOMC)
Ortofon X5-MC (late version) = 0.75mg (HOMC)
Ortofon MC Jubillee = 0.22mg
Ortofon MC5000 = 0.25mg

Now for some MM/MI examples that I have personally measured:
Shure / Jico SAS (for V15V) = 0.28mg
Shure V15VMR = 0.17mg (manufacturer spec, the one example I have measured came in at 0.23mg)
Pickering XLZ7500S = 0.2mg (manufacturer spec, the example I measured came in at 0.32mg)
Signet TK9E = 0.35mg

And one oddball LOMC:
Dynavector Karat 23RS = 0.09mg (!!)

In the above you have a number of examples of LOMC that have higher mass than more economical MM's.

There are a couple of MC's there that are very good low mass examples, but the MM/MI's are in the same ballpark.

Note: I have not yet measured the Technics EPC205mk3 I have, and the EPC202 - both with boron tube cantilevers, the EPC205Cmk3 should according to manufacturer specs come in at 0.149mg (which is substantially better than the very best from the house of Ortofon).

The LOMC's from the same period as the EPC205mk3 although also fitted with the Boron Tube cantilever, did not have their mass quoted.... presumably they are heavier.

The evidence of actual measurement as well as manufacturer specs appear to indicate that there is no tip mass advantage to being LOMC...
And that the best cartridges of any particular topology all have very low tip mass...

bye for now

David

 

[dlaloum]

ld: Yup, I'd also rather suggest to take tip mass specs with a grain of salt - also because it's often not quite clear whether it actually is equivalent tip mass or rather just the mass of the diamond... Nevertheless I'd consider Flavios list as good enough to consider the "lower moving mass myth" as busted.

Greetings from Munich!

Manfred / lini

Hi Lini,

as LD points out the ETM is usually an equivalent for the resonant frequency.

The Ortofon specs appear consistent with this - carts I measured that were correct (or within less than 5% of the spec) were:
320u, X5-MC, Digitrac 300SE, OM20

So it appears that this is the correct methodology for this particular measurement.

I agree that all manufacturer specs need to be approached with caution - and my measurements of the V15V seem to reinforce that - although the measured result was still excellent. (same for the XLZ7500S)

In any case - I think that measuring the resonant frequency does in fact provide an indication of how light a moving system is (even if the vagaries of physics are such that we are not seeing the precise actual ETM)

bye for now

David

 

[Mister Pig]

One uestion. How do you account for the effect of the suspension in these measurements? Does the compliance factor into the equation?

One thing to point out.

There are a couple of MC's there that are very good low mass examples, but the MM/MI's are in the same ballpark.

The examples you are using to validate this sentence are entry-ish level high output moving coils. Not LOMC. Not the better examples of this technology. And when adjusted for time period and cost, were probably less expensive than the best of the MM/MI you are comparing to. Also these cartridges are from an earlier time period in the development of MC cartridges. At that time these cartridges were of lower compliance, and the movement of the cantilever/coil assembly was intentionally restricted, and the preferred arm was high mass. So cantilevers needed to be extremely stiff and able to function in a high mass arm arrangement. This was a typical arrangement for an 80's and 90's era cartridge. While there certainly were deviations from this, such as the Accuphase AC3 or the Ortofon MC 2000 cartridges, they were not the norm. This is not the case with MC cartridge development, which has steadily moved to medium compliance designs and lower mass cantilevers. Also you are not going to see the best of the breed at the $300 price point, just as you did not see the best of MM/MI at $120 in the 80's. Couple that with economies of scale, when vinyl was not the niche market it is now, and you get different cost structures for building and selling cartridges.

EDIT: One thing I have often wondered is: Do cartridge manufacturers "dumb down" their low end products in order to create a hierarchy of performance? Are the cheap cartridge performance more limited than they should be? Can a cartridge manufacturer make a better cheap cartridge at a good profit margin? Just always been a thought that rattles around in the back of my head....some days I even remember it.

Regards
Mister Pig

 

[GreatTone]

I will say that if I had to choose between spending money on a great arm and a great cart, I would get the arm first. You will get much more out of a modest cart mounted on a great arm, than you will with a great cart mounted on a modest arm. I learned this when I went from an RB-300 to my Audiomods. At that time I was using a Grado Gold with 8MZ stylus (a modest cart), and the improvement in sound with the Audiomods was huge.

A couple of years ago I got my first LOMC -- the AT33EV, which I immediately loved. I got about 1000 hours out of it before the stylus wore out, just a month or so ago. I did the Audio Technica trade-in, and while waiting for my new AT33EV to arrive, I mounted a NOS cart I had picked up a while back: the Astatic MF300. This is a moving flux Japanese cart from the 80s I think, with an elliptical diamond, 4mV output and a standard aluminum cantilever. I have to say I thoroughly enjoyed listening to it during the few weeks it was on there. I have never had a cart with so much slamming bass. Soundstage was wide with decent depth, and everything was exceptionally musical -- like I was listening to the music, and not the sound, which was very relaxing.

But when my new AT33EV arrived, I found myself mounting it up right away. Then I remembered why I loved its sound so much: huge separation between instruments, singer's voice floating in 3D space, incredible air and shimmer around the highs, super detail and realism combined with musical warmth, etc. The only thing missing is that slamming bass. The Astatic is a higher compliance cart, and maybe a better match for the Audiomods. I have a headshell shim coming from Jeff (Audiomods), so that added mass may help give the AT33EV that last missing element, the incredible palpable attack on the bass, where you feel it in your chest on pretty much every record. But if I have to choose, I'll sacrifice that bass slam for everything else the AT33EV delivers.

I was thinking of moving up the food chain and trying a Lyra instead of replacing the AT33EV, but decided my money would be better spent at this time on either room treatments or speakers that are impervious to a really crappy room. But I'm sold on LOMCs after a lifetime of MM/MI/HOMCs.

 

[luckydog]

Nevertheless I'd consider Flavios list as good enough to consider the "lower moving mass myth" as busted.

Yup, I agree for this and other reasons.

One question. How do you account for the effect of the suspension in these measurements? Does the compliance factor into the equation?

'Top resonance' is mechanical self-resonance of the cantilever assembly, and suspension provides damping for it. More damping=Lower compliance. IMO the resonance is determined by ratio of cantilever rigidity to cantilever mass, in combination with armature inertia. In practice there seems little to split LOMC and MM, a wide range for examples in each camp. On balance I agree with David that mostly cantilever determines performance in this respect, and armature mass appears secondary. If anything LOMC seem to have slightly lower top resonant f as a class, and I think this perhaps fits with higher armature inertia and that seems common sense. But I wouldn't split hairs, I just doubt 'moving mass' holds the key as to differences.

Just another 2p worth awprint:

 

[Mister Pig]

Yup, I agree for this and other reasons.

'Top resonance' is mechanical self-resonance of the cantilever assembly, and suspension provides damping for it. More damping=Lower compliance. IMO the resonance is determined by ratio of cantilever rigidity to cantilever mass, in combination with armature inertia. In practice there seems little to split LOMC and MM, a wide range for examples in each camp. On balance I agree with David that mostly cantilever determines performance in this respect, and armature mass appears secondary. If anything LOMC seem to have slightly lower top resonant f as a class, and I think this perhaps fits with higher armature inertia and that seems common sense. But I wouldn't split hairs, I just doubt 'moving mass' holds the key as to differences.

Just another 2p worth awprint:

Ok next question then. what about coil to magnet gaps. Also in MC it seems that you can build larger magnet assemblies, and perhaps use smaller gap sizes. I also imagine you have more freedom to control the field the magnets form, and perhaps use a wider array of magnet materials. Are there any inherent advantages of using large static coil assemblies versus large static magnet assemblies?

Regards
Mister Pig

 

[Kingshead]

Cartridge manufacturers seem to agree that mass is very important, I would imagine their expertise in this is higher than most if not all hobbyists. Yes I understand they are in the business to sell merchandise.

Martin

 

[lini]

Mr. Pig: I think you're mistaken on that - 'cause there were very quite a few more compliant MCs back then, even comparatively highly compliant ones, like for example the Denon DL1000 on Flavio's list (and also the DL305). And cartridges like the DL1000 or the Audio Technica's AT1000 and the Yamaha MC1000/2000 imo also are very good examples that MC designs have already reached their peak in the 80s and rather haven't really moved on, just like MMs and MIs haven't either - which imo is understandable considering the market situation. Ever since then we're only getting slight variations, and top class implementations have become more expensive (and unfortunately often enough pretty ridiculously so...).

Greetings from Munich!

Manfred / lini

 

[lini]

(...) Are there any inherent advantages of using large static coil assemblies versus large static magnet assemblies? (...)

Rather the other way, as already mentioned quite a good bit above - from the electrical side a large static coil assembly isn't the best idea. But otherwise I really don't see that much of a difference. In fact I'd think that low output MM or MI designs with non-removable needle and built with otherwise equal top class ingredients could be every bit as good as top class MC designs.

Greetings from Munich!

Manfred / lini

 

[Mister Pig]

Mr. Pig: I think you're mistaken on that - 'cause there very quite a few more compliant MCs back then, even comparatively highly compliant ones, like for example the Denon DL1000 on Flavio's list (and also the DL305). And cartridges like the DL1000 or the Audio Technica's AT1000 and the Yamaha MC1000/2000 imo also are very good examples that MC designs have already reached their peak in the 80s and rather haven't really moved on, just like MMs and MIs haven't either - which imo is understandable considering the market situation. Ever since then we're only getting slight variations, and top class implementations have become more expensive (and unfortunately often enough pretty ridiculously so...).

Greetings from Munich!

Manfred / lini

While there are more than 3 or 4 high compliance MC designs from then, the list of low compliances ones were exponentially longer....

Kietsu
Kiseiki
Supex
early Accuphase
Audioquest
Crown Jewel
early Dynavector
Fidelity Research
GAS
Fulton
Ikeda
early Azden M's
JVC MC's
Linn MC's
Lyra
Micro Seiki

All of these companies and more subscribed to the low compliance design philosophy of the day for LOMC cartridges. I would say they far outnumbered the list of higher compliance designs.

Regards
Mister Pig

 

[Mister Pig]

Rather the other way, as already mentioned quite a good bit above - from the electrical side a large static coil assembly isn't the best idea. But otherwise I really don't see that much of a difference. In fact I'd think that low output MM or MI designs with non-removable needle and built with otherwise equal top class ingredients could be every bit as good as top class MC designs.

Greetings from Munich!

Manfred / lini

Oh I think they could too. Seems that is the approach that Sound Smith is using with their cartridges, and they are well received in the marketplace also.

Regards
Mister Pig

 

[thedelihaus]

...In fact I'd think that low output MM or MI designs with non-removable needle and built with otherwise equal top class ingredients could be every bit as good as top class MC designs.

Greetings from Munich!

Manfred / lini

Interesting point- as some are aware, there was a move by some to move away from plastic snap-on stylus assemblies and incorporate a better mounting method of removable stylus assembly for some of the MM carts- a good example would be the stylus assembly consisting of an aluminum block mount held tightly and firmly to the cart body by a brass set screw as found in the Signet TK-9/10, Audio Technica ATN-22/23/24/25, ADC TRX series, and a few others.

 

[thedelihaus]

...what about coil to magnet gaps. Also in MC it seems that you can build larger magnet assemblies, and perhaps use smaller gap sizes. I also imagine you have more freedom to control the field the magnets form, and perhaps use a wider array of magnet materials. Are there any inherent advantages of using large static coil assemblies versus large static magnet assemblies?...

I'm especially intrigued by this statement and the benefit of a larger magnet assembly/smaller coil assembly. For the MMs, and I assume MIs, it seems to be nearly reversed from my experience, with substantially larger coils packed into the body and a notably smaller magnet/magnetic iron piece structure.

 

[Ken Boyd]

Has any manufacture made a cartridge that instead of using a small magnet on the end of cantilever, put a small coil and excite it with voltage, in other words a field coil type of MM that would be basically a Hi output, version of a LOMC?

 

[GreatTone]

Has any manufacture made a cartridge that instead of using a small magnet on the end of cantilever, put a small coil and excite it with voltage, in other words a field coil type of MM that would be basically a Hi output, version of a LOMC?

There's the strain gauge cartridge, but it doesn't have coils:

http://www.sound-smith.com/cartridges/StrainGaugedetails.html

 

[Multiplex]

I'm especially intrigued by this statement and the benefit of a larger magnet assembly/smaller coil assembly. For the MMs, and I assume MIs, it seems to be nearly reversed from my experience, with substantially larger coils packed into the body and a notably smaller magnet/magnetic iron piece structure.

MMs have small magnets, but some MIs have big, powerful magnets. If it weren't for cantilever in my XLM/ZLM stylus assemblies, they would probably damn near stick there if I tossed them at my fridge... And, I'll bet a Grado body would too. Maybe that's why I tend to prefer the sound of most MIs that I've heard to most MMs. Though I do tend to find Shures to be pretty decent, I don't care for AT's MMs. I have found that the MIs that I have heard tend to have a thicker, deeper, and more lush midrange.

It sounds like the performance of high-gain/high inductance coils in most MM/MIs may be their biggest shortcoming... Makes me wonder how some of the lower output MIs like the Grado Signature series would compare to the Prestige series... I have never heard one. I wonder how it would compare to the sound of LOMCs?

With their tendancy to pick up EMF and RF, I always wondered why Grado even made low output bodies. It didn't seem practical, but if what I am reading here is true, maybe they were on to something.

 

[GrampaDave]

In a perfect cartridge the cantilever should be totally inflexible and pass on 100% of the signal to the generator.

I believed this too, but see Figure 9 in

"Optimizing the Dynamic Characteristics of a Phonograph Pickup"
AES Disk Recording Anthology, Volume 2, pp 213-220,
originally presented October 1965,
C.R. Anderson, J.H. Kogen, and R.S. Samson (all from Shure).

They simulated the tracking ability of a stylus with various amounts of compliance. (I am referring to the stiffness of the cantilever, not the suspension.) It turned out that unless it was also massless, an ideally stiff cantilever did badly, with a severe dip in tracking ability at resonance. Making the cantilever a little bit "bendy" fixed that.

Thank goodness, eh?

They did not remark on cantilever compliance's effect on frequency response.

Dave

 

[river25]

I have a question....

The whole purpose of the stylus is to extract the maximum information from the groove. So this is also highly dependant on the actual quality of the analog information cut into the LP.

The lathes or cutters that create the record therefore would determine this initial physical quality. Over the history of LP production I would assume these lathes/cutters increased in quality. So, my question is, would there not be ealier LPs that would not benefit from a MC cartridge because the LP does not have the information that would take advantage of this? Later LPs perhaps might as the initial cutting was performed by better equipment?