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cartridge loading

I am running a grado red with a project se II tube phono preamp. It is a mm cart that works on the tube box factory setting which I believe is 47kohm. I am getting some annoying hum and am wondering if any other settings on the tube box would be better. There are DIP switches that can be set for both mm or mc loading.
fromunda
fromunda OP
148 posts
 
thanks Atmasphere. Which setting would be 22,000 ohms? My manual lists for MM loading as such; 47kOhms/120pF
47kOhms/220pF
47kOhms/340pF
47kOhms/440pF
By the way what is pF?
curio's avatar
curio
305 posts
 
By the way what is pF?
(Fromunda)

PicoFarad
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rauliruegas
13,095 posts
 
Dear Fromunda: You have to try almost all those settings in your phono stage to achieve the best quality performance in your system.

MM/MI cartridges needs not only 47K ( some times different impedance value. ) but a capacitance load ( those pF you are asking for. ), these kind of cartridges are sensitive to capacitance loading.

Rgeards and enjoy the music,
Raul.
atmasphere's avatar
atmasphere
11,841 posts
 
If your preamp will not allow you to install the resistor, then you have to go with the switch positions they provide.

Personally I prefer to do as much loading with resistors as I can, rather than capacitance. I worry about the capacitor and inductance of the cartridge becoming a tuned circuit...
donaudio
129 posts
 
My preamp has RCA jacks for loading. What kind of resistors shold I be looking for and where can they be purchased? They have to have axial leads as I will solder them to the RCA plugs. Thanks, Don
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