Stored, used, crossover capacitor burn in / reforming time


2 years ago I pulled out a pair of 24 uF metalized polypropylene capacitors from my speaker crossovers. They had been in use for 15 years. I just put them back in for comparison with my replacement caps . How many hours would they take to fully burn in / reform again ?

jim94025

You will get 90% of what they sound like within the first 24 hours of play. Little change after that for the next couple of days of playtime. 

Cap data sheets do not spec "burn in" time to reach rated capacitance. PP caps do not dry up like electrolytics so there is no dielectric reform to worry about. Once you put the caps back in they will perform the same way they did all these years right off the bat.

My experience with MPP speaker caps (Mundorfs) was 48 hours.  Had some really interesting surround sound effects until that was over.

 

So after 25 hours, the speakers ( with my old  metalized polypropylene capacitors in the midrange) sound much like I remembered. Very fast, better transients and more separation, however a smaller soundstage and they are not as musical or involving as the Clarity's they replaced. They are still a bit leaner than I remember, but they were always leaner than the Clarity's. Maybe the solder connections are still in need of burn in, we will see. As with many things in our hobby, some recordings sound better with each cap and about 20+% are not as good. I may also try some VH Audio ODAM caps in that position, as reccomended by grannyring. Hopefully I'll get the speed and transients of the mpp's with better musicality and body. 

On that note, does anyone have a reliable method of buring in caps before placing them in the crossover? I've heard that the ODAM's take 200-400 hour's for their sound to mature.