Phono stage w/automatic Load-Impedanance.
**I am talking about the fact that if you hear tonality change with a LOMC seemingly due to loading, its on account of the behaviour of the preamp and not the signal from the cartridge.** I know that's what you're talking about. I made it clear that tonality change is NOT what I was talking about. What don't you understand? |
Many cartridges that make 0.2mV into 100 ohms can do so into 50 ohms as well. Its a small amount of wattage, but you can see in this example that in the latter case it would be making twice as much power as the former. This has to come from somewhere (the groove walls) and as such means that the stylus has become slightly harder to move. I know that's what you're talking about. I made it clear that tonality change is NOT what I was talking about. What don't you understand? Fleib, maybe you could outline what you *are* talking about as it is not clear from your posts so far. |
Atmasphere, From this thread: *In the absence of noise one might prefer to load down a MC because of preference. Damping a cantilever/generator might improve focus and detail, while wide open might increase stage and size.* *A phono cart is an electro mechanical transducer on the source end, but no electrical damping isn't necessarily better. Mechanical performance is the overwhelming determinant of cart performance, something that many EE's don't get. Loading, electrical damping can be a way to balance factors other than amplitude response and noise.* Why does Jonathan Carr recommend for Kleos: *Recommended load directly into MC phono input: 95.3ohm ~ 816ohm* ? http://www.lyraconnoisseur.com/Products/Products_Analog/kleos/kleos3.html If you say that's because of inferior phono preamps, I say it doesn't matter or it's an inappropriate response. It doesn't matter because this isn't about you, it's about the Phonata. It's an inappropriate response because your examples and consequences are misleading at best. Do you really think Kleos will start tearing up grooves if loaded at 100 ohms rather than 47K ? That's what you imply. Is every cantilever optimally damped? A MC cantilever is usually damped just enough to suppress mechanical high frequency resonance to between +3 to +7dB @ 20KHz. Of course usual isn't always and there are exceptions, like no cantilever or short ones. This is way outside the scope of this thread, but no-load always being better is a wrong assumption IMO. It's not right for any preamp all the time, and certainly not all MC's. Regards, |
My comments are based on an objective understanding (measurements, calculations, and simulations) of what a low-impedance cartridge generator is, what an interconnect is, what happens when the two are combined, what happens when resistors of various values are added to the mix, and what happens when extra capacitance is added. A low-impedance cartridge has an inductive generator, while a phono cable has significant capacitance. Put the two together and you get a huge spike at ultrasonic frequencies. These frequencies are much too high for any human to hear directly, but fall in a band that is likely to impair the linearity of the phono stage in much the same manner as excessive RF. When we "load down the cartridge", for the most part we don't affect what the cartridge does at all (unless the value of the load approaches or drops below the internal impedance of the cartridge). What adding resistive loading at the phono stage input accomplishes is to dampen the resonant energy of the ultrasonic spike, and give the phono stage an operating environment isn't so likely to trigger any latent non-linearity tendencies that the phono stage circuitry may have. The above comment was from jcarr, which seems to agree with what Atmasphere is talking about. http://www.whatsbestforum.com/showthread.php?15077-Cartridge- |
