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MM vs MI vs MC
- Thread starter watchnerd
- Start date
Was the the body I sent you?
Nice stylus collection. You might even get a couple of them to work for more than a day.
No. Picked it up off Yahoo Japan, attached to an EPA-B500/A501H in a T4P adapter. The arm was rough and seemingly not many people noticed what the cartridge was.
A few do work for more than a day, or they did. Haven't tried one for several years now - they're all slated for rebuild.
Retaining screw
I just acquired an EPC-100CMK3. Stylus is in unknown condition, cartridge is riding only about 1mm above the record, so I think it's safe to say that the suspension has seen better days. I believe this cartridge was supposed to be extremely flat, when new. It's really too bad that Jico doesn't make replacement styli for these.
Yes, the suspension on these rots... be very very careful with the one you have - I would suggest going to a really good retipper and asking whether they can replace the suspension...
The cantilever and needle are (arguably) the best ever made, or at least the lowest effective mass ever made. (that I am aware of)
So definitely worth while salvageing if at all possible - running it with the deteriorated suspension may result in disaster if/when it collapses fully - destroying the cantilever in the process. (this has happened to many !!)
And yes - I have a look at Jico every few years just to check whether they have issued a needle for these or their close sibling the EPC205p
Thank you for the advice, I don't plan to use it until I have it worked on.
I have been in contact with a highly esteemed retipper who has been able to replace the suspension on these in the past. He told me that he recently encountered an example that had a frozen screw, preventing him from accessing the suspension. I'm crossing my fingers that mine won't have the same issue!
Here is my newly retipped OC9ML/II. While on the way to the retipper for a minor issue with the cartridge body, it unfortunately came loose in the box and lost its diamond. Luckily, no harm was done to the cantilever. I elected to have it retipped with another ML (Namiki Microridge) stylus. The first images are using the low MC setting of my iFi Zen Phono at 1k Ω, while the second images are using a Signet MK12T SUT at the 20 Ω setting into the iFi Zen Phono MM at 47k Ω.
Left channel:
Right channel:
Left channel:
Right channel:
One to play with later...
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I apologize if this has been mentioned earlier. In the US, the popularization of mostly Japanese made MC cartridges happened in the early to mid '70s. [MC were sold earlier, such as the Grado and ESL--that I believe was a rebranded Ortofon SPU--but they were outliers] Much ink was spilt over why the MC was an inherently superior sounding design, when compared to MI or MM. I don't want to get into whether that was really the case, but many thought so.
Reduction in moving mass was one idea, however most MC were relatively low in the compliance department, so the decreased moving mass wasn't going to buy anyone superior 'trackability' (at least in the Shure V15 sense).
Also, at that time line contact shapes were becoming prevalent, a spinoff from the discrete four channel JVC Shibata geometry. But you could get those diamonds in MI and MM, so any sonic improvement attributed to MC wasn't that, either. 'Exotic' cantilever formulations (boron, beryllium, diamond, ruby etc.) could be had in all the multiple designs, too.
An early MC champion, Mitchell Cotter (working through the editorial offices of Peter Aczel), argued that the MC design's less susceptibility to FM distortion secondary to 'axial pumping' or a 'back and forth' displacement of the stylus within the groove, was the key. This was secondary to typical suspension parameters of MC, as opposed to the usual MI/MM cartridge.
A MC cantilever was usually tied from the the back by a small length of 'piano wire', allowing the stylus to move in an up and down and circular motion, following the groove patterns, but not a front to back motion. Alternately, the rubbery suspension of the MI/MM allowed the stylus to move longitudinally, back and forth, in addition to circular groove induced motion. This back and forth movement induced an unintended frequency modulation.
This idea was not something Cotter came up with, but rather pointed back to an article published in the Journal of the Acoustical Society of America by J. Rabinow and E. Codier (Ordinance Development Division, National Bureau of Standards, Washington D.C.), Volume 24, No. 2, March 1952. The paper is hidden behind the Journal's paywall, but can be found on line elsewhere. Also, a freely available digest can be found at Google Docs, NBS Technical New Bulletin, March 1953.
I have scanned that abstract/review below.
I posted this in the other "courteous" thread but maybe it is better here. To me the advantage and disadvantage of an MC cart is that it is not sensitive to loading. This means you will get a similar FR independent of loading (advantage) but it is difficult to try to adjust the FR via loading (disadvantage). Using the script and a STR-100 I measured my cart and then using Rephase created a FIR filter to try to flatten the response. When I applied the fir filter to the original file and ran the script again it seemed to "work" and the FR was pretty flat. When I switch back and forth with and without the FIR filter there is a subtle difference and I think I prefer the "filtered flat" response but it could be bias of course.
Technically speaking what is the disadvantage of using a FIR filter to get flat FR vs using exotic materials and techniques in the mechanical world? Obviously at some point the mechanical system can perform so badly that filtering can't really help but what point is that? For small 1 or 2 dB adjustments is filtering OK or is it always a compromise?
See below Before, Fir Filter, After.
Technically speaking what is the disadvantage of using a FIR filter to get flat FR vs using exotic materials and techniques in the mechanical world? Obviously at some point the mechanical system can perform so badly that filtering can't really help but what point is that? For small 1 or 2 dB adjustments is filtering OK or is it always a compromise?
See below Before, Fir Filter, After.
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It's a Gertrude Stein thing. Amplitude, frequency, phase, intermodulation, crossover are all distortion, for sure.
Excerpts from the actual paper:
It should be noted that while the aforementioned theory shows that the tangential forces on the stylus are of the even harmonic type, the distortion that the tangential motion produces as a result of these forces contains only odd harmonic components. This is so because the tangential motion affects each half of the audio wave symmetrically.
In the crystal cartridge used... when the needle tip moves forward, the end of the pickup arm moves down. Since the needle may be considered to be acted upon by a spring which tends to locate it in the central position, it can be seen that under frictional excitation the needle will oscillate forward and back, and the pick up arm oscillating up and down accordingly, the frequency of the oscillation being a function of the compliance of the needle mount, the compliance of the spring counterbalancing the weight of the oscillator, and the effective mass of the pick up arm.
When single frequency records are played... it will be noted that without the needle being tied back... there is no appreciable difference in the lateral recording, but a very great difference in the longitudinal output.
untied v tied back
A surprising result of these tests is that the fore and aft motion is basically of the same frequency as the lateral motion, while theory would indicate that it should be twice the frequency. Several possible reasons... One is that the head is offset with respect to the tangent to the record groove so that the needle motion is in reality at an angle to the groove and not along the true radius. A second is that as a result of friction of the arm pivot bearing, the pressures on the two sides of the needle are not equal, and the differences in friction account for the large single-frequency component.
How audible was it?
A number of efforts were made to determine the extent of distortion of the normal output signal attributable to tangential vibration. These efforts met with failure.
The measure of actual distortion effects is complicated by several factors. One is that the conditions that give rise to to pinch effect, tracing distortion, record deformation, groove skating, etc. Another cause of difficulty is that... the tangential motions set up by high frequencies are small but that the tangential motions caused by low frequency recordings are large. However, the tangential motion of, say, one-thousandth of an inch has very little effect on the electrical output when a wavelength is perhaps a hundred times that, so for single frequencies the effect can be said to be small,,, but when recordings are played where many frequencies are present, as is usually the case in music, cross-modulation is immediately produced.
There have been several popular cantilever-less designs that, one would suppose, are less immune to any effects of 'needle drag distortion. In the '60s Denon cartridges used a version of Rabinow and Codier's 'piano wire' suspension to lock the cantilever in place. Decca and Ikeda cartridges don't use a cantilever in the usual sense.
Ikeda sourced Jeff Rowland MC
eliash
Senior Member
On the other hand, an iron core cross, where the typical MC-coils are wound upon, produces a significant amount of "Barkhausen-effect noise", when iron moves in the strong stationary magnetic field. Easily recognisable when the load on the tip is varied by e .g. the tonearm lift on a still-standing platter (e. g. entry level MC Benz ACE-S).
Sounds like a worn-out car suspension and is caused by magnetic (Weiss'-)domain-borders shifting around in the iron, while the changing field is being picked up by the coils.
Therefore, according to my opinion, when investing in MC, go for the really expensive iron free coil carrier designs, e. g. made from ruby (which of course have the drawback of yielding only limited electrical dynamic range)...MP (moving permalloy; also located in the stationary magnetic field) seems less susceptible to this effect from my experience with Nagaoka´s MP500...
(check out here: https://en.wikipedia.org/wiki/Barkhausen_effect ;
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