Sorry for the newbie questions but I need some help with the Pearl Phono boards. First, what is the purpose of the capacitors C14 and C16 ? Second, Wayne wrote in the article that the 40V power supply listed is just a suggestion. Is there something else that I should try or is that one good enough ? Thanks for the help.
These capacitors are for loading an MM type cartridge. The user can put in his favorite value. I see I didn't talk about them in the article.
gate capacitance?
resurrecting an old thread here 😎
i'm putting together my parts list for the pearl and I'm also wondering about the cartridge loading and I haven't found all the answers in the forums. I'm using a goldring 1024 mm cartridge (2mv, 47k Ohm, 150-200pF) and maybe grado black. the resistance is right on. as for capacitance, I'm wondering if the input jfet gate capacitance should be taken into account. the data sheet says 30pF gate capacitance each and there are four in parallel, for 120pF. So to be right on spec, I'd need to add 30 to 80pF, correct? Also how sensitive is this loading? I assume higher values would roll off the high freq, although the spec seems very low compared to mc carts..
having fun with this 😀
resurrecting an old thread here 😎
i'm putting together my parts list for the pearl and I'm also wondering about the cartridge loading and I haven't found all the answers in the forums. I'm using a goldring 1024 mm cartridge (2mv, 47k Ohm, 150-200pF) and maybe grado black. the resistance is right on. as for capacitance, I'm wondering if the input jfet gate capacitance should be taken into account. the data sheet says 30pF gate capacitance each and there are four in parallel, for 120pF. So to be right on spec, I'd need to add 30 to 80pF, correct? Also how sensitive is this loading? I assume higher values would roll off the high freq, although the spec seems very low compared to mc carts..
having fun with this 😀
oh but then there's cable capacitance! probably more than 100pF anyway
so i'd guess the circuit is perfect for me as-is; no input cap needed! am i on the right track?
so i'd guess the circuit is perfect for me as-is; no input cap needed! am i on the right track?
Hi,
MC-carts are a very different animal compared to MMs.
Don't forget that manufacturer's recommendation can also be a bit misleading as they're often very generic (I think there are some Ortofons where the rec. capacitance goes from 300-500pF, quite a nice large range).
If you're really want to get serious about this, get several pF-caps, hook up your phono-amp to your soundcard and do some frequency response measurements for each cap.
But, honestly, that isn't strictly necessary to enjoy music 😉
You're already on the perfectly right track, seems you need no additional capacitance at all.
Have fun, Hannes
MC-carts are a very different animal compared to MMs.
Don't forget that manufacturer's recommendation can also be a bit misleading as they're often very generic (I think there are some Ortofons where the rec. capacitance goes from 300-500pF, quite a nice large range).
If you're really want to get serious about this, get several pF-caps, hook up your phono-amp to your soundcard and do some frequency response measurements for each cap.
But, honestly, that isn't strictly necessary to enjoy music 😉
You're already on the perfectly right track, seems you need no additional capacitance at all.
Have fun, Hannes
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