Cap upgrade advice needed

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timind

Cap upgrade advice needed
« on: 13 Oct 2015, 10:13 pm »
Hello,

I want to replace one of the caps in my Meadowlark Audio Kestrel crossovers and before ordering replacements I want to check something. The cap to be replaced is an electrolytic 36uf 100v. I can't find an exact replacement anywhere. After reading some of the threads in this circle I thought I might find an answer here.
The only thing I've found close is a 36uf 250v metalized polypropyline cap. Am I correct in thinking the difference in the voltage rating won't matter? Also, will going from electrolytic to polypropyline be ok sonically.
Also, I did a cursory search on the Sonic Craft website but didn't see what I was looking for.
Here's a pic of the crossover. The purple cap is the one in question.


Early B.

Re: Cap upgrade advice needed
« Reply #1 on: 13 Oct 2015, 10:31 pm »
For a few dollars more, consider getting a crossover makeover, especially if you plan on keeping those speakers.

timind

Re: Cap upgrade advice needed
« Reply #2 on: 13 Oct 2015, 10:43 pm »
For a few dollars more, consider getting a crossover makeover, especially if you plan on keeping those speakers.

I plan on keeping these speakers as long as I can hear the music. What do you mean by "makeover?"

Jeff

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Re: Cap upgrade advice needed
« Reply #3 on: 14 Oct 2015, 03:22 am »
Hello,

You have lots of options...  First, the cap you are replacing is 10% tolerance if you are lucky.  That means that it could be 32.4uF to 39.6uF and still be in spec.  Lets assume that PM hand picked all the values.  If he culled 95%, the best he could probably consistently do "might" be 3%, so 34.92uF to 37.08uF.  The second scenario is highly unlikely.  Anything above a true 50VDC will be fine.  If you use cheap film, you will notice excessive brightness from 2.5K to 9.5K.  A warmer, smoother film cap is more coin, and you will likely have to parallel two caps.  A good film cap is probably not worth it unless you are willing to upgrade the high-pass cap and resistor.  If you want to use a high grade electrolytic, parallel these two caps: http://www.soniccraft.com/product_info.php/mundorf-cap-plain-15uf-70vdc-50vac-p-4070 and http://www.soniccraft.com/product_info.php/mundorf-cap-plain-22uf-70vdc-50vac-p-4074  Purchase L1 matching, and request low values for a combined 36uF.  I'm sure we can handle that.

If you think you might want to greatly improve these speakers, and have an extra $350 burning a hole in your pocket...  Mundorf Supreme Silver/Oil for the high-pass, and replace the Caddock resistor with a Mills MRA-12.  Replace the electrolytic (likely the bass shunt) with a 18uF paralleled pair of Sonicap G1s.  :green:

timind

Re: Cap upgrade advice needed
« Reply #4 on: 14 Oct 2015, 08:54 pm »
Thanks for the reply Jeff. I'm going to place an order for the electrolytic caps you linked.
I should've mentioned I had replaced the Caddock resistor as I wanted to reduce the value by 1 ohm. I did use a Mills MRA 12 resistor there.
The Supreme Silver Oil caps are little pricey for these Kestrel speakers.

timind

Re: Cap upgrade advice needed
« Reply #5 on: 14 Oct 2015, 09:04 pm »
Order placed.

Glad to have your expertise on this website.  :)

Jeff

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Re: Cap upgrade advice needed
« Reply #6 on: 20 Oct 2015, 01:25 am »
Thank you  :green:

Let us know how it turns out.