Soundminded, I think that you did not separate the 2 separate resonances and how they then add together to make the 4 pole low pass filter that comprises the Shure MM cartridge. Perhaps, I read you wrong?
The FR curves published by many respected laboratories over and over again showed TOTL MM cartridges in the 1960s and 1970s had exceptionally flat FRs to 20 khz. I could cite countless examples by the mainstream audio hobbyist magazines of tht era such as High Fidelity which used CBS Laboratories (later CBS Technology Center) for its tests, Hirsch Houck Laboratories, and Audio Magazine. 10 khz square wave response showed excellent fast rise time with little or no ringing which as I've stated is simply one other way to demonstrate that the combined electrical and mechanical resonances added up to a device which exhibited overall wide flat frequency response. By contrast, MC cartridges like Ortofon were horrible with 5 to 7 db peaks in the 15 khz range. The square wave method of viewing it showed considerable ringing in the 10 khz test, in other words, the identical result as the FR test predicted. This may have been considered deisrable by some because it offset the nearly universal characteristic of hf rolloff of most loudspeakers of the era such as AR3/AR3a. What's worse, the MC cartridges requried at least 2 grams of tracking force or more to operate properly while the best MM cartridges typically did well at 1 g or less. Low cost equalizers for consumers didn't exist yet, the Altec Acousta-Voice 1/3 octave equalizer cost $900 per channel and was reserved only for recording studios. Cheap and poorly made or deliberately underdamped cartridges like Pickering and Audio Technica exhibited the same hf peaks as MC cartridges. This may explain why rugged MM cartridges like Pickering PAT-2 were so popular among mass market all in one systems which chose to use what for them were high end equipment of the type insead of ceramic types like Astatic and Sonotone. KLH was among those who used Pickering. Pickering was of course the low end market product of Stanton whose 681 and 881 series cartridges were among the better models available. The other contender was ADC. The original XLM may have had the highest compliance of all cartridges at 65 x 10 to the minus 6 cm/dyne but it was so fragile it was easily damaged and required a top notch tonearm to operate properly.
While the MC manufacturers have improved their products over the decades, the same principles and considerations apply. The cost of the better MC cartridges is absurd. Unfortunately, the after market replacement styili for old MM cartridges were manufactured with elastomers which hardened over time and now even NOS after market styli perform poorly at high modulation. Only original manufacturer styli from companies like Empire and ADC still work well. Right now I'm hunting down a replacement for 999VE (not VE/X.) Two bad ones so far, one from Walco and another from Pfeinstahl. Been looking since the maid destroyed the last one five years ago. It could have been worse.
Who persuaded me to buy an Empire TT and 999VE in 1968? A salesman at a trade show who sold Thorens, Shure, and SME. That was the alternate being considered at the time. He told me I'd be very happy with Empire and he was right.
While the MC manufacturers have improved their products over the decades, the same principles and considerations apply. The cost of the better MC cartridges is absurd. Unfortunately, the after market replacement styili for old MM cartridges were manufactured with elastomers which hardened over time and now even NOS after market styli perform poorly at high modulation. Only original manufacturer styli from companies like Empire and ADC still work well. Right now I'm hunting down a replacement for 999VE (not VE/X.) Two bad ones so far, one from Walco and another from Pfeinstahl. Been looking since the maid destroyed the last one five years ago. It could have been worse.
Who persuaded me to buy an Empire TT and 999VE in 1968? A salesman at a trade show who sold Thorens, Shure, and SME. That was the alternate being considered at the time. He told me I'd be very happy with Empire and he was right.
Why no ringing? Because the Shure cartridges roll off the inherent ringing on the square wave record. Yes folks, if it doesn't show ringing, it has limited frequency response!
Usually Ortofon and similar cartridges had a 15K DIP at 15K, due to the fact that scanning losses kicked in. Their resonances were usually around 30-60KHz. Measured most of them in our lab, over 35 years ago. These curves were regarded to have a 'saddle' shape. Ortofon was just fine, in this regard, especially in the early years.
In the 1960's, I had a similar turntable. It was called a RECOKUT, or (rumblecut) as I nicknamed it. It too, used a large Pabst synchronous motor with belt drive.
I don't think you will ever get it right. You were wrong last time we had this discussion years ago and you are wrong again. If the square wave doesn't ring....it means the system does not have an FR peak. Sheeesh. Get a book....and read it. Start with a math book about differential equations. When you get to the part about ordinary second order differential equations and how they apply to Newton's second law and the LCR circuit, you might get it. Plot the graphs with different damping factors. Then go on to a book about Fourier and Laplace analysis. Plot those graphs. Eventually it just might sink in.
You couldn't weasel out of it last time and you won't this time either. The test record is worthless if the test signal rings. If it rings, it isn't a square wave, it's distortion. The purpose of a test record or signal is to provide a known input and compare it to the output of the system under test. The deviation from ideal in the output characterizes where the system's limits are. Is that how you test all your projects, with distorted test signals?
The way to separate cutter ringing from stylus/vinyl ringing is to run the test at two different turntable speeds.
These square waves (and the unintentional cutter ringing thrown in at no extra charge) are terrifically revealing test signals.
The CBS 112 test record had ultrasonic ringing on the square wave, because it was 1/2 speed recorded. When you play it back at speed, you get the ultrasonic ringing with wide-band cartridges, with this test record. That is why a Shure looks so good with it.
I did a search here for some cartridge responses and square wave photographs using the CBS 112 test record. I found a number of significant tests in 'High Performance Review' published in the 1980's. For those who have access to these 'Journals' this is what I found:
Shure V15V 16uS RT SQ wave on P.50, HPR Vol.2,#2
Shure Ultra500 12uS RT SQ wave on P.48, HPR Vol.3,#4
Ortofon MC20II 10uS RT SQ wave on P.31, HPR Vol.1,#1
There were many other cartridges measured.
There seems to be a separation between OVERSHOOT, and after-ringing. Shure cartridges had plenty of overshoot about 20%, but little after-ringing. This is due to the fact that they are not as wide band as moving coil cartridges. Most MC cartridges had risetimes of 10uS or less, even 7uS was recorded. They show the inherent ringing made by the cutter resonance when CBS made the test record.
It is interesting that the Shure Ultra500 had MORE after-ringing than the V-15V. This is because the new improved Shure Ultra500 had more effective ultrasonic bandwidth, actually pretty darn good, for a moving magnet.
Shure V15V 16uS RT SQ wave on P.50, HPR Vol.2,#2
Shure Ultra500 12uS RT SQ wave on P.48, HPR Vol.3,#4
Ortofon MC20II 10uS RT SQ wave on P.31, HPR Vol.1,#1
There were many other cartridges measured.
There seems to be a separation between OVERSHOOT, and after-ringing. Shure cartridges had plenty of overshoot about 20%, but little after-ringing. This is due to the fact that they are not as wide band as moving coil cartridges. Most MC cartridges had risetimes of 10uS or less, even 7uS was recorded. They show the inherent ringing made by the cutter resonance when CBS made the test record.
It is interesting that the Shure Ultra500 had MORE after-ringing than the V-15V. This is because the new improved Shure Ultra500 had more effective ultrasonic bandwidth, actually pretty darn good, for a moving magnet.
FR Test data corroborated by oscillophotographs of 100 hz and 10 khz square wave response for Empire and ADC cartridges in the 1960s and 1970s showed little ringing (usually one low amplitude well damped cycle) or no ringing and flat response to 20 khz. That is adequate for audio signals. Ultrasonic response is superfluous except for playing RCA CD4 records. Besides, practically no records have any ultrasonic signals cut on them anyway. That signal would be worse than useless if it were there only contributing unnecessarily to noise and distortion. Of course there are those who don't believe that. But then they must never have heard of Fourier.
They are declared to be, but in fact usually they are not. Make your analysis and bring exact results, it is very simple. You might be able to analyze R-L/C//R circuit yourself. The load capacitance has limited possibilities to optimize response, and it affects roll-off frequency as well.
ADC Astrion 17.5 uS RT p.50 Vol.1,#2
Goldring 910 16 uS RT p.76 Vol.2,#1 570mH
I am sure that the Empire could not rise time any faster or have extended bandwidth either, unless it was especially made for CD4 operation, then it would show the ringing on the test record also.
Goldring 910 16 uS RT p.76 Vol.2,#1 570mH
I am sure that the Empire could not rise time any faster or have extended bandwidth either, unless it was especially made for CD4 operation, then it would show the ringing on the test record also.
Pavel, 47K IS THE WORLD STANDARD! No fooling around, no Mickey Mouse, it is the only fixed value that MM phono cartridge manufacturers are SUPPOSED to design around.
Do you yet understand how the whole frequency response of a MM magnet is derived?
It is the combined output of both the MECHANICAL and the Electrical resonances, not one or the other.
The MECHANICAL resonance of the MC cartridge is higher and outside the audio band, because it would cause a huge bump in the frequency response if it were in the audio band. Usually 30K-60kHz. I measured at least a dozen of them, myself. Moving magnet can allow the undamped mechanical resonance to be BELOW 20KHz as the peak developed can be attenuated by an OVERDAMPED electrical loading that creates a 4 pole low pass filter. Ask Shure engineers about it, if you don't believe me. They are the ones who taught me!
Do you yet understand how the whole frequency response of a MM magnet is derived?
It is the combined output of both the MECHANICAL and the Electrical resonances, not one or the other.
The MECHANICAL resonance of the MC cartridge is higher and outside the audio band, because it would cause a huge bump in the frequency response if it were in the audio band. Usually 30K-60kHz. I measured at least a dozen of them, myself. Moving magnet can allow the undamped mechanical resonance to be BELOW 20KHz as the peak developed can be attenuated by an OVERDAMPED electrical loading that creates a 4 pole low pass filter. Ask Shure engineers about it, if you don't believe me. They are the ones who taught me!
And an excellent design it is too. Flat to the edge of the required passband and then a sharp cutoff filter to eliminate spurious ultrasonic noise which adds nothing of value but could cause intermodulation distortion in the audio passband. Exactly what other systems like FM stereo, IF amplifier alignment, and others are intened to do also. It also reduces sensitivity to induced stray RF noise. Empire cartridges were also mu metal shielded as an added precaution.
Empire was bought by a Swiss company and then seemed to disappear from the audio equipment market. Today, what it became sells batteries and earbuds I think.
John, I certainly know this. And I could provide an equivalent circuit diagram of the moving magnet transducer, containing both electrical and mechanical converted to electrical components (BTW, I have studied just that at the university, electroacoustics, that covers transducers, and I have Engineering degree in this). There is no reason to prove one's knowledge. And I have also measured a lot of MM cartridges.
The reality is that MM cartridges have more or less damped resonance at the high end of their frequency response. Electrical amplitude overshoot sometimes tends to equalize a loss of high frequencies, that's correct. BUT, the frequency response is never flat. It always has a tolerance within 1dB or more.
Even web space shows measurements of many MM cartridges of different producers. 47k is a standard, it is a kind of usable value, but not any optimum. Many cartridges have optimum rather at 22k, taking into account standard signal cable capacitance like 200pF. The additional capacitance does not necessarily help, it may easily rise the amplitude overshoot value and decrease F(-3dB). Mainly for the reason that MM cartridges have resonance at the high end of their amplitude response, more or less damped, they do sound different.
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