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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
mofimadness's avatar
mofimadness
4,982 posts
 
The "pf" (picofarads) setting is usually only needed by MM, (moving magnet) cartridges. Shouldn't really matter with moving coils.
t_bone
1,182 posts
 
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.
bifwynne
2,206 posts
 
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
bobsdevices
100 posts
 
MC Cartridges do not like capacitance. You should reduce it to the minimum possible and also use interconnects with low capacitance.
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