AudioCircle
Other Stuff => Archived Manufacturer Circles => Hagerman Technology => Topic started by: hagtech on 17 Jul 2003, 08:17 pm
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Ever wonder what the proper resistor loading of your cartridge should be? First, try what the manufacturer recommends. But keep in mind the value is system dependent. Makes a difference what cables and phono stage you use.
What I have found (and confirmed by an independent article in audioXpress and others) is that you want to minimize the capacitive loading. Never add capacitance. Then tune the ultrasonic resonant response by lowering the load resistance. Normally phono stages have a 47k input resistance, but most MC cartridges suggest loading as low as 100 ohms. To understand why, I've written a short white paper on the subject.
http://www.hagtech.com/loading.html
Keep in mind step-up transformers translate the impedance by the square of the turns ratio. So a 1:10 step-up into a 47k phono stage actually presents a 470 ohm load to the cartridge.
My phono stages have all been designed to have a super low input capacitance. This pushes the resonant frequency higher out of the audio band and allows you to operate with a higher loading resistance for the equivalent damping. This frees up the cartridge to do it's thing and extend bandwidth as high as possible.
jh