Cartridge Loading- Low output M/C

2channel8   6-1-2018
I haven't been able to measure my phono cable's capacitance. My multimeter just reads 0.0 F, even though it has a uF range. 

As a rough ballpark approximation, a typical phono cable may have a capacitance in the vicinity or 25 pF (picoFarads) per foot or so, corresponding to 125 pf for a five foot length.

125 pF is 0.000125 uF (microFarads), and 0.000000000125 F (Farads), so it would be understandable that your meter indicates 0.0 F.

Regards,
-- Al 

Specifically to phono cable from TT RCA box to phono stage.....Cable capacitance does matter with regard to LOMC cartridges. Lyra specifically suggests using a low cap cable, they do not recommend high cap cables. 
I also used a Morrow Audio PH6 Grand Reference phono cable for some time and when I finally asked Mike he said 390pF/mt and I was shocked! He said he never heard HF rolloff with his cables, I tend to agree but then I assume it is because you have to load at a lower setting, which is not good for the cantilever, you run the chance of stiffening the cantilever.

Once I switched to AQ Cougar at 40pF/mt and loaded my Delos to 475 ohms.That's when the higher dynamics and resolution came into play, it was a jaw dropping moment. The Delos performance rose many levels, really everything just got better.

On my Musical Surroundings Nova II I have the setting at 100pF (the new model settings are 100/200pF, the older were 200/300pF), Michael Yee changed it. In general I too hear no difference but have it set to lowest closest to my cable rating.

I tell everyone just find out all the specs you can, then go from there. You can't make the proper settings till you know all the info along the signal path. 

Cheers

Al, Thanks for bringing up the question of metering. I do own a Sencore LC meter that can measure down to the pF level. If I want to measure the capacitance of a cable, do I just place the Sencore probes on the hot and ground of the cable, with the other ends (hot and ground) unterminated? That seems right, but I am not sure.

I also think this might be a good place to summarize the points made by Ralph, Al, Wyn, etc.  First, no one is saying that there is only one correct load for a typical LOMC cartridge with very low internal resistance.  Second, I think Wyn has conceded that his first model for the behavior of such a cartridge when driving a phono stage was based on some usually false assumptions: (1) that such cartridges have coil inductance as high as 0.5mH, and (2) active RIAA correction in the phono circuit, which is atypical of most of the “best” phono stages capable of working well with such cartridges without a SUT.  Assuming inductance in the low micro Henry range and passive RIAA, we should keep associated capacitance as low as possible.  Under all these conditions, it is not inconceivable that a high resistive load, e.g., 47K ohms, might sound better than the more typical values of load resistance used by us audiophiles, e.g., 100R.  In my case, I can say that the difference between 100R load an 47K is not huge by any means, but once I had tried 47K for at least 2 or 3 of my LOMC cartridges, I’ve developed a preference for it.  What I hear is as predicted, highs seem more open and extended.

@catcher10, Why 475 Ohms? Why not 1000?
BTW, I have no report on 100K yet. Too much new digital music to listen to at the moment. 

Dear @catcher10: """  I tend to agree but then I assume it is because you have to load at a lower setting, which is not good for the cantilever, you run the chance of stiffening the cantilever. """

that was in reference to those Morrow cables. Now, I understand what that loading electrical can or could has some effect on the cartridge compliance and you said that exist a chance to.....

I think that to really stiffening the cantilever something really extraordinary has to happens.

How did you measure and what found out when changing from 500 ohms to 100omhs loading about that cantuilever stiffness that puts it on risk and how can we know when that could happens. Which the loading window limits to play inside in safe way. If any.? which is the role of the cartridge suspension dampers in all this load subject. How can be affected?

I ask that because not only my personal experiences in my system for years but what other audiophiles in their systems experienced when I was at their places. Different systems with different LOMC cartridges. They never reported anywhere a cantilever problem with their cartridges because a 100ohms load not me either.

How can I be aware of it?

Your anwers truly appreciated. Thank's in advance.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.