Cartridge Loading.....Part II
I read last night the below noted discussion with great interest. It's a long post but worth the effort and I found it interesting.
It started me thinking about the amount of loading on my moving coil cartridges. Years ago I purchased my first MC Cart, a very nice Benz Micro Glider, medium output of 0.5 mV as I recall. At that time I inquired about loading here on Audiogon. I was convinced, via discussion, by another member, that 300 Ohms was the magic number, so I thought.
Time moved onward and my second MC Cart is currently a Lyra Delos, again medium output 0.6mV. Both carts had Boron cantilevers', 6 nines oxygen free copper coils and line contact diamond stylis. When I set up the Delos I did not change or even consider 'loading' changes. That was a grand mistake.....
Well, thanks to this specific thread I started to second guess myself . (you can do this when retired and more time is on your hands....)
My take from this recent thread is as follows. Load at 100 Ohms or at 47K Ohms with a quality MC cartridge. I opened up my Conrad Johnson EF1 Phono Stage this afternoon. Found it set at 500 Ohms loading. 100 Ohms is not an available setting. Damn...All these years I've been running the wrong loading, and on two carts, back to back... I don't recall why I set the loading at 500 Ohms. Faulty logic.
I reset the loading to 47K, buttoned things up and called the wife in for a listening session. Sure as heck both of us noticed the highs were crisper and more 'apparent' than in the recent past. Not a huge difference, but yes, a difference.. Hard lesson learned!
So, you smarter folks on this site might banter amongst yourselves, but in reality there are those of us, behind the curtains, reading and listening! I just wish I hadn't wasted all those years listening to the incorrect load setting!
Ending with a sincere thank you very much!!
Lou
Dear @wynpalmer4 : I understand you but due that some gentlemans as lewm just did not reads the whole cartridge loading threads then are reduntdant on the issue one and again and other gentlemans what want is to " win " the discussion or " hit " to some one else and of course always exist the stupid and the stupidity. . Sorry that disturb you and sorry for what I will posts next.
R. |
@lewm : this is what Wyn posted before your post: "" I was the one who wrote previously about Faraday’s Law and Lenz’s law in support of Carr’s assertion. For your information, I have designed DIY phono stages that embody the characteristics that he espouses- very high supersonic overload characteristics for example- and are extremely compliant to the RIAA characteristic, very low noise, and essentially unmeasurably low distortion. There are several hundred of them out there... In any case, there are no conservation of energy issues here. The mechanical energy of the groove wall reaction to the gravity induced downforce (i.e. the forced motion of the stylus) "uses" Faraday’s law to produce an output EMF (voltage). That voltage produces a current that complies with Lenz’s law- which essentially defines the inductance of the coil and occurs as an energy conservation consequence- and that current is defined by the total impedance of the coil- the inductance, the capacitance and resistance- the equivalent load impedance in fact. The back emf is just due to the inductance, and is proportional to the frequency. For a 10uH inductance at 20kHz, the impedance is about 1.6ohms, so relative to a 100 ohm R the back emf generated that opposes the input voltage is about 1.6/100 of the input voltage, and 90degrees out of phase, so it’s about 0.1dB of the signal amplitude. Yes, the back emf opposes the motion of the cartridge, but it’s very small compared to the generated voltage- which is due to the conversion of mechanical energy to electrical energy as described above- and essentially can be ignored in calculating the dynamics of the cartridge arm system. """
and years before in the same issue he posted:
""" effects of heavy resistive loading you state could be definitively true- certainly not on tracking which is demonstrably false based on IM tests on tracking performance that I have incidentally performed as a function of load. While mechanical impact does occur as a result of electrical load- there is some back emf necessarily generated by the signal current that affects the mechanical motion, but a quick back of the envelope calculation using Lenz’s law and the 10uH cartridge suggests a 2 orders of magnitude difference between the generated signal and the back EMF for a 100 ohm load at 20kHz- certainly not enough to cause tracking issues """
and this post too years ago by Wyn:
"""" By the way, I constructed a model for the cartridge back EMF using Lenz's law and incorporated it into my simulations.
After all those years why you did not learn or at least try to understand about that issue? sorry.
R.
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That's unfortunate. I was/am familiar with Lenz's Law. I was simply hoping you could elucidate on how the input of the phono preamp (where the load is) provides a back EMF, or it I simply was misunderstanding what you wrote. I'm perfectly open to learning something new. |
Dear Raul, I recently posted a URL from Wiki that contains a figure which I thought is instructional in understanding Lenz' Law. Some describe Lenz' Law as the electromagnetic equivalent of Newton's Third Law of Motion. My opinion-less post with the URL preceded the one from Wyn that explains Lenz' Law in words rather than pictures. Other than that, I have been sitting on the side lines. I did not and do not take any position, because I am not qualified at the level of the best contributors, but I am here to learn. So I wonder why I am now the target of your invective. What makes you think I have not been reading the posts by Wyn, Ralph, and Dave, the only 3 people on this thread who are qualified to discuss the subject at hand? Cut back on the coffee, take a tranquilizer, get some therapy. Do whatever the f*** you want but leave me alone, please. |
@lewm , I did not saY THAT. tHIS THREAD IS ONLY A FOLLOWER ( tITLE: CAN YOU READ THAT: PART II ? ) of not only another thread because the more critical about happened years ago and in the middle exist other threads here and in wbt forum and other forums. It's not invective but you normally just do not read all the information not only in this thread subject but in other thread audio subjects and this is not invective but a fact. Sorry to disturb you.
R.
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