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Capacitance Question

So I have a clearaudio maestro and performance turntable going into a simaudio lp5.3 preamp. The maestro wants a 100 pF load. The turntable has a 1.2m cable with a capacitance of 156pF. So that's about 177 or so. Am I correct that the 0pF setting in the lp5.3 is the way to go?

Why would clearaudio make a tonearm cable that could match the capacitance of their cartridges?
djn04
lplayer
28 posts
 
let your ears decide.
dan_ed
2,451 posts
 
Djn04,

You can tune this by realizing that the cable capacitance and that which you can set in the LP5.3 make a pair of series capacitors.

C = (c1 x c2)/(c1 + c2)

In theory, since you know the target value for C as 100, and you know the value of the cable, c1, you can then solve for c2 which would be the value you would want from the LP5.

In reality, you may not have a setting that gives exactly 100pF, but you can still use this to understand what you are doing. And, you just might find a value a little different that you think sounds best.

HTH, and good luck.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Hi Dan,

Actually that's not correct. They're in parallel, not in series, so they simply add together.

Cable capacitance is "in shunt" between the signal conductor and the shield or other return conductor, and the phono stage input capacitance is across/between/in shunt with the signal and return connections on the input jack.

Best regards,
-- Al
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