Interesting: The URL offered by Atmasphere gives access to calculators for both RC and RL type filters. Using the RC calculator, I cranked in 150pF as an approximation of capacitance of my tonearm wire plus that of the phono input stage (which is a cascode and thus not sensitive to Miller capacitance, anyway). The equation itself tells you right away that fc is inversely related to both R and C; thus it is no surprise that when R = 100 ohms, fc is >10,000,000Hz. When R = 47K, fc comes down to ~22,000Hz. So if you look at it as an RC circuit, 47K would not make for a bright sound, compared to 100R. I then cranked the same values into the RL formula, were fc is directly proportional to R. I used 50 microHenries as an approximation of the inductance of the MC2000 (a typical value for a LOMC cartridge). Not surprisingly, in this case, when R = 47K, fc is much higher than when R = 100 ohms, but even with 100 ohms, fc is >300,000Hz. So again, 47K is not going to make for a brighter sound that we could possibly hear. In the actual situation, fc is a function of R, L, and C. Comments of Atma and Fleib, or anyone else, appreciated.
Cartridge impedance loading question
Hi folks. I have a Shelter 501 Mk 11 cartridge going into a Lehmann Black Cube phono pre. The Shelter's impedance is 12 ohms. The recommended load impedance in the Shelter specs is ambiguous…
Other than a user retrofittable option the Lehmann moving coil options are 80, 100, 470 & 47k ohms. What would you be using?
Thanks!
Other than a user retrofittable option the Lehmann moving coil options are 80, 100, 470 & 47k ohms. What would you be using?
Thanks!
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- 44 posts total
- 44 posts total