Saying that a (working) phono stage has zero input impedance is similar to claiming to travel at the speed of light
but this is exactly what i do when i travel back in time to find some rare cartridges
Cartridge loading
Hey Lew. It appears as if this guy has a good take on what is going on with the 0Ω http://phonoclone.com/diy-pho4.html I quickly simmed the circuit and it appears as if the input Z is frequency dependent and around 0.001Ω @ 10hz and increases by a factor of 10 for every decade which puts it at 1Ω @ 10khz and 10Ω @ 100khz. how you translate this into an easy to understand input impedance for the masses is not an easy task. Is 0Ω 100% accurate? no... but for the majority of the audio band it is close. Just try to explain a frequency dependent variable to a group used to values being ruler flat form 20-20K. In the end I do not think there is anything disingenuous with the claims but once taken out of the context of being an audio generalization for the masses it does become problematic. dave |
@lewm ;: I re-read your post and your hypotesis is only that and I doubt some one can " jump " here to confirm your hypotesis that can " impede it " . """ wonder whether the load resistor might affect the magnitude of that phenomenon. """ I can see that you like to make all more " complicated " when the issue posted by atmasphere was diferent to what you posted and I can't understand why not we can go step by step: why add more " phenomenos " to the main issue. I wonder why? Anyway, you are free to post what ever you want. R. |
Raul, I have no idea what you are trying to say. Please clarify. Thanks. From the one sentence I think I do understand, how can one subtract the effect of the load resistance when the entire question revolves around the value of the load resistance? Ralph says that low value load Rs tend to impede the cartridge's ability to trace HF. My idea, for good or ill, is an attempt to explain how that might be the case, but I am saying that the load resistor, for an LOMC, is in parallel with the coil resistance, which is already usually less than 20 ohms. So the parallel sum of the value of the coil resistance plus the load resistor will always be less than 20 ohms. In other words, the load resistor does not make a big difference and maybe therefore should not have much effect on the magnitude of any "back EMF" generated at the coil/magnet interface. This would lead me to disagree with Ralph, but the whole issue is a bit over my head to begin with, and I seek input from others who know more than I do. There's another way of looking at it, too. |