@tester007 7mOhm ESR @ 120Hz is an internal impedance of the capacitor (Equivalent Series Resistance) measured at 120Hz - lower is better. It represents losses in capacitor. 29.3A @ 120Hz is the max charging current at 120Hz - higher is better. Value at 10kHz is likely for use in switchers (SMPS).
With higher breakdown voltage in the same case size - something has to give.
Your amp can deliver a lot of current (375W per channel) while capacitors in power supply are charged in narrow pulses of high amplitude. There is no way to know for sure if 23.4A in 100V version is enough. I would stick with exactly the same as original or at least one with the same specifications.
Ripple current Q for amp capacitors
I have a pair of EAD powermaster 1000's in my theater. The older one is at least 25 years old I think, and developed a slight hum I could hear in the theater. So I popped it open, did a cap inventory and replaced them all. I checked every one of the main amp caps as I pulled them out, and surprisingly they all seemed really good still, within tolerance.
But I didn't replace the two large filter caps. I had searched for a 100,000uf CD cap online, clicked on the link to Mouser, and purchase 4 (2 for each amp.. figured I would do both). However when all the caps arrived, I realized in my haste the link was to 10,000uf caps instead.. DOH! So I went back and tried to find the matching caps.. expensive! And to top that off, when I "could" find some (Ebay mainly), the date code was around the year 2000 as well so they were about the same age. Digikey has a lead time to about December.. and also over $200cdn each.
The original spec was a Cornell Dubilier, 100000uf 50v -10%/+75% cap. They do have a 100v version in stock, half the price, and actually shorter than the 50v version.
But my question is this.. when I search online for whether a low or high ripple current is preferable for an audio amp, I get both answers.. low is better because then it filters better, to high being better because that means the cap can handle more ripple and heat. Which is correct?
The 50v version is:
7mOhm ESR @ 120Hz, 29.3 A @ 120Hz, 38.09 @ 10 kHz
the 100v version is:
10.2mOhm ESR @120Hz, 23.4A @120Hz, 24.57A @ 10kHz
I have no idea if these numbers are incredibly close, or meaningfully different.. and which is better?
Showing 2 responses by kijanki
@tester007 Sorry, I've never done it. When I replaced them once I just turn power on.@atmasphere would know, I'm sure, perhaps he can chime in. |