# one large cap, or a few added up?

For a cap in series to a midrange (120uf) is it better to get one at that value, or is it better to use 3 to 4 in parallel like 30, 40 & 50 uf so it adds up to 120 uf ?

thanks
koestner
11 responses
 07-23-2009 8:47pmIsn't there additional phase change from using multiple caps?John C. 07-23-2009 9:24pmEverything else being equal, I would think it would be better to use several smaller caps in parallel. The smaller caps would likely have lower stray inductance, and lower esr (equivalent series resistance), both of which would then be further reduced by the parallel connections with the other capacitors (parallel connection reduces inductance and resistance, while it increases capacitance).The only difference in phase effects that I can envision would correspond to the difference in stray inductance, which, although probably minimal, would be in the direction of favoring the parallel combination.Regards,-- Al 07-23-2009 11:11pmI would do as Al suggests; a method which use to be in vogue was to take one large cap and bypass it with a small one, this supposidly gave much of the sound of the small ones in a simpler configration but it has been a long time since I built anything so this may be out of date. 07-24-2009 12:33pmthanks guys. It seems that it is hard to find a 120uf cap so I will have to use a combination. Is it better to use 5 24uf, or to stagger the values like 50,33,25 and 12 which total 120uf as well?John 07-24-2009 1:17pmHi John,It's hard to say without having detailed information on esr, stray inductance, etc., and it may not make a significant difference either way, but my instinct would be go with whichever approach (within the same make/model series) minimizes the use of capacitors which are physically largest.In other words, if the 50 and/or 33 are significantly larger than the 24, go with the five 24's. If not, and if the 12 is significantly smaller than the others, then perhaps go with the staggered values. My thinking is that a physically larger capacitor is likely to have significantly greater stray inductance.Regards,-- Al 07-24-2009 3:21pmI'd suggest to use several of the same Capacitors from the same batch and match values as closely as you can. Probably the most important will be to choose something fairly musical and yet reassonably priced and long lasting such as Ansar Supersound polypropylene. Ceramic would be terrible. I would be concerned about mix and match in the high signal level path - caps change shape slightly and "ring" with high voltages applied across them - it might be better to have a closely matched set or you may lose clarity. 07-24-2009 4:30pmI have heard proponents of both theories. There are some who swear by "cascading" caps such as 10uf/7uF/4uF/2uF/1uF to make 24uF. There is another camp that says that the caps should all be of the same size when paralleling them in order to avoid time-smearing the sound, such as 6 X 4 uF to get 24uF.In my Infinity RSIIb crossovers I'm using the latter approach. 07-24-2009 6:49pmAn excellent source for high quality caps, and Michael will also match your caps to within 1%: (http://www.percyaudio.com/Catalog.pdf) I've used DynamiCaps in Maggies with great results. auriCAPs are also an excellent cap: (http://www.partsconnexion.com/t/catalog/CapacitorsFilm.html) Whatever caps you use, be certain to observe proper lead(outer foil)orientation: (http://www.audience-av.com/capacitors/a_applications.php) Another service that Percy offers is marking the outer foil leads on the caps he sells. Keep in mind that when you first replace the caps, and fire the system back up; it probably won't sound great. It takes a while, with operational voltages, for the dielectric in a high quality cap to "form". 07-24-2009 7:53pmIs there any way to break-in new caps without having to have them installed in my speakers. It seems that they will need 100 to 500 hours before they are "right". That's a lot of time! Could I just wire them up in parallel and plug them in the AC outlet for a few weeks? 07-24-2009 8:09pmYou might want to be a bit more civilized. Try this:(http://phonoclone.com/diy_rack.html) Read the last line, as you will be dealing with non-polarized caps(forgive his spelling). 07-25-2009 5:13pmThanks for all the responses. I think I will be going with 5 Clarity SA 24uf caps in parallel for a combined total of 120uf. I will hold off on a bypass cap because there seeme to be two camps on this. I will try it without bypass for a while, then get some, and see which way I prefer.Thanks to all... John