By the way, just by curiosity, did somebody made a MM cartridge with Neodymium magnet ? They are so light and powerful.Another question, maybe I'm missing something, conceptually you could increase the strength of the magnet without changing its mass soon you have >100% efficiency by your argument?
By the way, just by curiosity, did somebody made a MM cartridge with Neodymium magnet ? They are so light and powerful.
I was just wondering the same thing, Shures had 5mV out long before neo-magnets. In a quick search I did find someone mention a MM cart with 15mV sensitivity.
Sorry Ed the coefficient of eletro-mechanical reciprocity varies from ~0 (strain gauge) to some larger number where the point is efficient transmission of power/work. The Grado has a small metal disk weakly coupling the field of some fairly substantial neo-magnets. It's clear that if the coils were free to move and you ran current through them you might get some relay type action. The assumption of large reciprocity for any electrical motor system is a mis-conception. Lucky, I trust his computations/measurements, stated MM carts are in the tiny fractions of a percent. You can compute the work done displacing the cantilever against the suspension and the work done on the disk by 5mV, they are orders of magnitude apart.
Then think the 10Hz tone arm resonance and damping the entire system with a few mV at the coils.
Scott & George,
We really didn't communicate. Having put more than a small voltage into a MC phono cartridge it didn't really budge.
Now reciprocity calibration is used for microphones and loudspeakers. For phono cartridges if I had any old ones around I would just glue the tips of two together and see what the transfer efficiency was. Suspect it would be almost zero.
My feel is that DC voltage or resistive loading will have almost no effect.
By the way, just by curiosity, did somebody made a MM cartridge with Neodymium magnet ?
"The Audio-Technica AT150LMX Dual Moving Magnet Cartridge features a Gold evaporation tapered
cantilever and ML (micro linear) broadband VM vibrating system of stylus. This is a unit with high
power Neodymium magnet and C.C.A.W. voice coil."
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RNM,
I will take joy in every day you wake up uncomfortable and can still participate with us!
George,
We may need to work on your sense of humor.
ES
I will take joy in every day you wake up uncomfortable and can still participate with us!
George,
We may need to work on your sense of humor.
ES
I was just wondering the same thing, Shures had 5mV out long before neo-magnets. In a quick search I did find someone mention a MM cart with 15mV sensitivity.
Shure specs. the 44-7 with 9mV
Simon, you too are in my secret friend list.RNM,
I will take joy in every day you wake up uncomfortable and can still participate with us!
George,
We may need to work on your sense of humor.
ES
A great although somewhat difficult to read book.On a slightly related issue: just scored the attached. Written in the year I was born.
Jan
To my astonishment I bought an auction copy on eBay some years ago, and the seller didn't even mention that it was inscribed by Bode on the FFEP! Very very rare afaik.
A great although somewhat difficult to read book.
To my astonishment I bought an auction copy on eBay some years ago, and the seller didn't even mention that it was inscribed by Bode on the FFEP! Very very rare afaik.
FFEP?
Front Facing End Paper?
se
Standard book term: Front Free End Paper (as opposed to the front pastedown). Both terms applicable to hardbacks.FFEP?
Front Facing End Paper?
se
I've gotten lucky a few times with book inscriptions. In one case I bought a copy of B. F. Skinner's notorious Verbal Behavior, from a professional bookseller. Years later I noticed it had an inscription, again on the front free end paper. It also had the owner's stamps here and there. It was from "Fred" and inscribed to Sylvia Thorpe.
At a book and autograph show I asked a rather-unhappy autograph vendor how I might go about determining if the Fred was Skinner. He said Oh I don't know---there's probably some damn society or something for him that you could contact. There was. I made a copy of the page and sent it, and received a reply from the President, Julie Skinner Vargas. "Yes, that is definitely my father's signature".
When I revealed this to a late bookseller I'd asked about it, he revealed that he knew Skinner, regardless of books in which a "B. F. Skinner" appears on some covers, signed things "Fred". If I had said it has been signed B. F. Skinner he'd have known it was a forgery.
At a book and autograph show I asked a rather-unhappy autograph vendor how I might go about determining if the Fred was Skinner. He said Oh I don't know---there's probably some damn society or something for him that you could contact. There was. I made a copy of the page and sent it, and received a reply from the President, Julie Skinner Vargas. "Yes, that is definitely my father's signature".
When I revealed this to a late bookseller I'd asked about it, he revealed that he knew Skinner, regardless of books in which a "B. F. Skinner" appears on some covers, signed things "Fred". If I had said it has been signed B. F. Skinner he'd have known it was a forgery.
Considering the complexity of the whole arm, cart, cantilever system vs frequency I don't see the effective mass telling the whole story.
I recall a review of a bargain turntable where a flexural resonance of the arm at ~350Hz showed up in the frequency response, the motor in that case is definitely working against a lot more than the effective mass you give. I would think the fact that you can easily hear the sound from the cartridge when playing an LP would beg the question that there is more going on.
There is only one arm I have not heard sound from and that is the Basis Vector or his super arm. A very nice arm from a very bright guy.
There is only one arm I have not heard sound from and that is the Basis Vector or his super arm. A very nice arm from a very bright guy.
The mechanical engineering sounds wonderful, I can do without "In the audio range, capacitance and inductance of a cable changes radically as the frequency changes". 🙄
What is it about audio?
What is it about audio? Why does it attract those who lack the rudiments of electrical engineering?
Is it the large range of frequencies? The fact that listening requires specific amounts of time? The large potential dynamic range?
Baffling.
The mechanical engineering sounds wonderful, I can do without "In the audio range, capacitance and inductance of a cable changes radically as the frequency changes". 🙄
What is it about audio? Why does it attract those who lack the rudiments of electrical engineering?
Is it the large range of frequencies? The fact that listening requires specific amounts of time? The large potential dynamic range?
Baffling.
What is it about audio? Why does it attract those who lack the rudiments of electrical engineering?
Is it the large range of frequencies? The fact that listening requires specific amounts of time? The large potential dynamic range?
Baffling.
Part of it is that it is relatively low level technically. Even with rudimentary knowledge (or even none at all!) you can with a bit of luck put something together that doesn't sound half bad.
It's only a small step to tell yourself you know it all.
Jan
Standard book term: Front Free End Paper (as opposed to the front pastedown). Both terms applicable to hardbacks.
Gotcha. Thanks!
se
Its just a typo. Read "magically" instead of "radically" ;-)"In the audio range, capacitance and inductance of a cable changes radically as the frequency changes".
What is it about audio? Why does it attract those who lack the rudiments of electrical engineering?
Is it the large range of frequencies? The fact that listening requires specific amounts of time? The large potential dynamic range?
Baffling.
AJ happens to be an BSME but does have a physicist on staff. Turntables and tonearms are more mechanical than electrical. He trusts math and measurements. His ears ain't to bad either.
And the usual background in 'aerospace/defense'. No disrespect to AJ, but in 2015 does that count for anything?
I'm not sure if I find that reassuring, but thanks for the correction.Its just a typo. Read "magically" instead of "radically" ;-)
Actually I know a couple of MEs who understand electronics as well or better than a number of EEs.
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