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I've known of these for awhile, as they are a non-electrolytic capacitor in large values at fairly reasonable pricing via NOS or used.
Being that a capacitively loaded sealed box involves larger capacitances than the average audio or industrial grade poly cap unless paralleling for value, these Unlytic types fill that niche with reliable long term use involved. Hopefully better sonics also will result. Through Don Radick's recent experiments, Tony Gee's Black Box, and my PC project; i've come to the conclusion that 500-600uF tends to be close to the sweet spot for 8 ohm loads. I also used that value in the EMP highpass/warmth notch.
It just so happens ebay had a listing for 600UF/300VDC Unlytics. The price was right, so i grabbed some of them. Be aware the shipping was not cheap. I'll report my findings as things progress....
Comments
Even with shipping, that's not a bad price for a 600uF film cap. I really liked the bass out of the RS270 in that box, much tighter than a ported box.
True that the 200uF Solen s are in the $60 range last i checked.
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Have you ever looked into motor start capacitors?
https://ebay.com/itm/334172816724?
Ron
Start caps are not a good idea, as they are not meant for continuous duty. I doubt that ABS is actually a film cap by looks alone.
Run caps are okay, and I've used some metal-canister types from ASC and GE in the past. The GE ones sounded like poop, but I really like the ASC 386X and 387X models.
Just thought I would post the ECI caps in case nobody here had seen them before. They actually make even larger value Unlytic caps meant for full conversion to film-cap power supplies. I've not gone to that degree myself, but Steve Fishe priced them and found the cost was too steep for him to go all-in.
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I realize they are advertised as film caps, but they sure do look exactly like every electrolytic cap I've worked with over the last 40 years of my career. If you think about it electrolytic caps are a film cap... just not the metalized film we like to hump as far as audio goes.
The Unlytic UL30 are dry nonpolar (no electrolytes) and film. The 600uF has an ESR of 0.0031 ohms too.
https://www.ecicaps.com/wp-content/uploads/ul30-series-unlytic-lt-sup-gt-reg-lt-sup-gt-series.pdf
There are other series of Unlytic caps too, for example:
https://www.ecicaps.com/wp-content/uploads/UP3_Full.pdf
They are made to mount into the same locations as the Electrolytics they should be replacing. That is why the ECI look so similar.
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Are you sure they aren't just playing you?
Being film and nonpolar can't be wrong or it'd be false advertising.
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Only one way to find out, disassembly.
Obviously, but that's too expensive to just throw away. I will add too, that they were only off a couple uF from value. I would say these are much tighter than 10%, and closer to 1% tolerance.
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https://www.electronicproducts.com/film-caps-directly-replace-electrolytics/
https://www.ecicaps.com/rd/
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