C1 and C2 also affect this - they are in a feedback network too, to complicate things.
Most MM cartridges are designed for 50k - the capacitance requirements vary more, typically in the range 50pF to 300pF, including cabling.
Most MM cartridges are designed for 50k - the capacitance requirements vary more, typically in the range 50pF to 300pF, including cabling.
When you can listen to an MM cartridge with an amplifier where the phono load resistance is variable (e.g. from 10k to 100k) , you may come across some interesting audible findings 😉
I have a mid-MC cartridge, specified for ">200 ohm" input impedance. I have a phono stage capable of loading at 47k, 1000, 500, 200, and 100 ohms. 1000, 500, and 200 all sound the same. 100 sounds a bit rolled off or "softer". 47k sounds a bit brighter, more "present"; might just be a bit louder?
Looks like a perfect candidate for a MC step-up transformer feeding into a 47k-ohm load in support of a MC cartridge.
MC is completely different kettle of fish - capacitance is irrelevant, loading should be significantly higher impedance than the cartridge, here 500 ohms is probably the one to go for.
A phono stage that tries to handle both MM and MC on the same input is rather a compromize, alas, since MM requires low capacitance, low current noise amp, MC requires ultra-low voltage noise amp. Something like a bootstrapped ultra low voltage-noise JFET can work for this, but its more common to see separate MC amp that can be switched in.
A phono stage that tries to handle both MM and MC on the same input is rather a compromize, alas, since MM requires low capacitance, low current noise amp, MC requires ultra-low voltage noise amp. Something like a bootstrapped ultra low voltage-noise JFET can work for this, but its more common to see separate MC amp that can be switched in.