PF SETTING FOR MC CARTRIDGE WITH SUT


I have a low output MC cartridge, My Sonic Lab Ultra with 0.6 ohm internal impedance. I am using a My Sonic Lab Stage 302 SUT which is connected directly to my MM Phono stage. Could someone explain what "PF" setting I should be using in my phonostage? The range in 50-750 in increments of 50. I had read that a good rule of thumb is to take the cartridge impedance and multiply by 10 which would be between 50 and 100 pf? The recommended impedance load for this cartridge run through a MC phono pre is 200 ohms. Look forward to any advice.
ssolman
Ditto what Mofimadness said but nix on your arithmetic (0.6 ohms x 10 is 6, so if need be, I'd set at 50pf). I cannot think of a situation, personally, when I would add more than the absolute minimum amount of capacitance (pf) for an MC cart. I will leave the question of adding capacitance to MM carts to others.
Mofi and T_bone: your post states that pF is generally relevant for MM but not MC cartridges. Would you consider MI (moving iron) cartridges to be in the same category as MM?? My cartridge, a VPI Zephyr, is a MI.

The Zephyr is hooked up to my phono pre with custom cables that have a capacitance rating of 16pF per foot, times 6 foot length, say 100pF. The problem is that the Xephyr seems to ask for no more than 200 pF downstream, but my phono pre alone has an input capacitance of 200pF. Thus, I am about 100 pF over the recommended level.

Any thoughts??? Thanks
MC Cartridges do not like capacitance. You should reduce it to the minimum possible and also use interconnects with low capacitance.
According to theory, moving coils should be immune to capacitance changes. But in audio, theory isnt always right. Trust your ears and leave it set on the setting that sounds best to u. Yes moving magnets and moving iron cartridges behave the same way and they are very sensitive to capacitance, some require low capacitance and others like the shure v15 series require about 400pF to get the flattest response. Check the cartridge mfrs. instructions for a good starting point and then experiment with different values until u like what u hear. As for the guy with too much capacitance in his preamp, I just heard of a way that u can lower the total capacitance by soldering a small cap in series with each of the tonearm leads. When caps are put in series with the circuit the total capacitance drops just like resistance drops when resistors are put in parallel. You can use ohms law to determine what value of capacitance u need to put in series with the phono leads. I have never tried this yet, but it sounds believable according to theory. But in audio theory is not always right! Hope this helps and Happy Listening! Shay
I understand (I think) why the capacitance should be as low as possible for a moving coil cartridge plugged directly into an active gain stage. The OP said he has his cartridge plugged into a step up transformer and the SUT into the MM input on his phono stage. Is it the case that the phono still sees a moving coil cartridge and that the SUT is "invisible" so to speak?