What most people don't realise is that the MM loading is the SUM of the C's.... if the phono stage has 200pf (which is very common) - then you need to add the capacitance of the cable ... a typical 1980's TT would be 100pf - making a total of 300pf.... which would work great for a Shure, or Ortofon MM, but typical AT MM's work best down at 100pf to 200pf... making them almost impossible to properly optimise on many setups!!!
Hence I personally stress to people that if they want to use MM's they need to have a phono stage with as little capacitance as possible and then use a low C cable (like LC-1) ... adding capacitance is very very easily done - you could use a more standard cable, or make some loading plugs with capacitors in them... - and the better phono stages often have switchable C load...(or the facility for loading plugs).
Depending on the stylus/body combination, some configurations work best with capacitance of 500pf (or more) - the majority though are around 200pf (and if you are fond of classic AT designs.... less, lots less!)
