Passive Crossover Caps

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famousmockingbird

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Joined 2010
I am replacing some capacitors in some old Klipsch Heresy's. I would like to use Polypropylene type caps without spending an arm and a leg. I have to place an order from mouser anyway so I would like to order the caps from them. I came across some caps I think might work. The datasheet says they are for active crossover networks so I am hoping they will suit my application.

Datasheet: http://www.mouser.com/ds/2/315/Capacitor%20Leaded%20Film%20%28ECW-F%28D%29%29-215017.pdf

Anybody use these caps in crossovers? Will they work for my application? If not what caps are you using and why?

Thanks
-bird
 
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AndrewT

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Joined 2004
motor run capacitors work well as crossover capacitors.
values from 10uF to 100uF are available in 250Vac rating at reasonable prices.

But by adopting a low esr plastic film capacitor you will probably have to change other components to bring back the frequency response engineered in by the speaker designer.
Adding a resistor in series with the low esr cap may be any easy way to make the crossover perform as intended.
 
infinia

infinia

Member
Joined 2005
AndrewT said:
motor run capacitors work well as crossover capacitors.
values from 10uF to 100uF are available in 250Vac rating at reasonable prices.

But by adopting a low esr plastic film capacitor you will probably have to change other components to bring back the frequency response engineered in by the speaker designer.
Adding a resistor in series with the low esr cap may be any easy way to make the crossover perform as intended.
Click to expand...


even if he used modern day non polarized electro's to replace like for like, that issue might remain due to improvements in those.

I would NOT do a global replacement to film types, just the series elements
 
infinia

infinia

Member
Joined 2005
shunt caps are bypassing the signal and they usually benefit from some extra esr damping, the series caps provide the actual current through the voice coils so they are more critical, but hey if you got the funds go wild.

it's madness putting 100 uF of expensive film caps on a woofers LPF and then adding a couple of ohms in series with it. I see these web sites that make their money from crossover components eg Jensen.
 
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famousmockingbird

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Joined 2010
I will attach a schematic but I don't see any parallel caps, only series.

I didn't think about the esr in the original caps being part of the design and going with lower esr film caps could be a bad thing. I have some Nichicon VP series 2.2uF on hand that I will try out first, probably better than the original which is in there now.

Nichicon VP: http://www.mouser.com/ds/2/293/e-vp-23529.pdf
 

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T

Tweet

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Joined 2015
Looking at that schematic I hardly think you should worry about ESR.

The crossover is hardly exotic. If anything should be replaced it would be the woofer's series iron cored inductance with a low resistance air cored inductor of the same value.

The poorest performing component used in any passive crossover has to be the inductor. Modern capacitors are generally of close tolerance and are well made to suit the purpose. Inductors on the other hand introduce power loss and irregular frequency response if iron cored, an 'air cored' inductor of low resistance would give a smoother performance.
I notice the schematic provides no impedance correction at all to any of the drivers which would mean a less than optimized performance from the crossover network.
So any concern about ESR with regards to what capacitors to use is neither here nor there.

C.M
 
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famousmockingbird

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I put the bi-polar electrolytics in for now. Since there are only four capacitors in the network and they are really easy to replace I figured what they heck, for all of an hour of time I can just put something better in next time if the sound quality is hindered. Tomorrow I can hook em up and give a listen.


I got some capacitors from Bob Crites a long time ago for some Heresy II's that I believe were Sonicaps that worked out good.
 
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Jeff Glowacki

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Joined 2013
Face is correct. Shunt caps are often in series when viewing a parallel network. They have a considerable effect 1-2 octaves above and below the xo point.

Replacing the low-pass inductor with a 12ga copper foil yields nice results with this speaker, especially if you are driving them with tubes. However, the capacitors make more difference here.

Most of the caps you linked to would bore a hole in your head if you put them in those speakers. At least the electrolytics will side towards the warm. After a little break in, they are apt to sound better than those cheap films. The guy who suggested the motor runs... With this speaker, they are apt to sound pretty good.

ESR is a non-issue here. While I am "Mr. Sonicap", and they are currently on Sale, they would not be my recommendation either. If you had the coin: Jupiter Vintage Flat Stack 2.2uF 100VDC, Sonic Craft On a budget: Kimber Kap 2.2uF 200VDC, Sonic Craft ,but we only have 4 left ;)
 
freddi

freddi

Member
Joined 2005
hey djk - that should be the cat's meow for Heresy I - what's a good cap for a K-horn? - the old Aerovox seemed better than the Obbligato motor run. The whole thing is muddy as my walls vibrate and the EM K33's q seems high. I like the Heresy much better than my K-horns.
 
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