Why is everyone so against electrolytic caps in crossovers?

[luvvinvinyl]

It's been a few years since I bought caps at PE. I was rehabbing several pairs of EPI speakers, over a span of time, and bought a bunch of 1% PMPE 10uf caps. I see they're about $7 per, now. I can't remember what I paid, but it damn sure wasn't that much. Seems it was about half that, IIRC. Since there was only one per box, it didn't seem too expensive to me, and the results were most pleasing.

JBL, Rogers, Infinity, Rogers, JMLabs, or some other highly complex design, and I'd probably be in the "Let's save some money" camp.

 

[Frank Sol]

Speaker people I respect say caps , at a certain level , are indistinguishable. Say a $20 sonicap vs $200 'whatever'

 

[89grand]

Just guessing... If you were to ask a speaker designer would he rather use film or electrolytic caps for the mids & tweets I dont think he would choose electrolytic

Yeah, I can believe that to be true, but I'm talking about people that remove all the lytic caps and replace them with something else. The speaker was never designed that way so if it sounded good before when it was new, "better" caps don't necessarily make the speaker better, it may sound worse since it wasn't intended to be that way.

On that note, what's a good affordable electrolytic cap brand to use?

 

[Naptown Rob]

They also used that damned foam that rotted out.
Just sayin'....

 

[Dr. Morbius]

Ah, unfortunately, it doesn't work that way. Shunt caps can have at least as much effect on the signal as pass caps, often more.

The scientific truth is that caps add distortion when:

1- They have audio voltage drop across them. (This is hard to explain to non-engineers.) Filter and crossover caps have audio voltage across them when they are operating near the crossover or filter frequency. Less so above and below. Coupling caps should never have audio voltage drop on them. Etc.

2- They are operating at freqs where their Z is comparable to related source and loud impedances.

But, people vastly over-state the problem with 'lytics. With the exception of a giant fraud concerning motherboard caps a few years ago, any decent electrolytic from the last 20 years should have few problems with longevity, esr, resonance, microphonics, distortion, etc.

-k

Seriously? These Krell manuals are worthless!

I'm going to owe a lot of people an apology as I've been stating they didn't really matter for a few years. Not sure where I read it. Could have been the DIY crowd at Parts Express. Not really sure.

I had some bad electrolytic caps on two Epox motherboards about a decade ago. Seems like every one of them leaked but the system ran stable, even when overclocked a bit.

 

[Ohighway]

Why not try a simple experiment with the smallest value cap, for your tweeter.
Buy the cheapest Polypropylene or Mylar capacitor you can find and do your own personal cap shootout v.s. the new electrolytic.

I did something similar to this several years ago. I pulled a pair of vintage Klispchorns out of storage. One worked fine, the other... there was no tweeter output. Traced it down to a bad capacitor. (1uF or 2uF, I forget which) Just to prove things out I ran down to Radio Shack and got a cheapy electrolytic, popped it in, and the tweeter worked. Later when I went to rework the crossovers , I used Solens purchased from parts express. So ultimately I was able to compare the original oil capacitor from the 'good' Klipschorn, a cheap electrolytic, and a Solen. Frankly, I couldn't tell the difference in sound.

I'm not sure I understand when people mention about designers 'voicing' the speakers using specific capacitors. Is this true, or just some folklore that keeps getting repeated over and over? I tend to believe it's the latter.
Has anyone actually talked with a designer who claims to have 'voiced' a speaker using a specific type and brand capacitor? Or are they just assuming this was the case?

Other than maybe super high end manufacturers, I'm thinking the designers designed crossovers using what was budgeted for, that being, electrolytics. I don't buy that they insisted on a certain brand, but probably what they got the best price on. And if that supply dried up they'd use a similar product from another manufacturer as long as it met basic specifications.

Interesting that ConradH finally mentioned something that few do. The fact that drivers change over time. So.... even if you hunt down those elusive original capacitors to retain the so called 'voicing' , it's not gonna' be the same as original. So maybe the better capacitors will somewhat offset that or, just as possible, they might make it worse.

I think there is a case for using the better capacitors as the film/foil and poly caps (if I'm to believe what I hear) tend to last longer, stay in spec longer, and have a lesser failure rate than electrolytics.

Just my $0.02

 

[kirk57]

My comment about 'voicing' pertained to the higher ESR of electrolytic caps vs film caps, not a specific cap per se. And yes, a higher ESR cap (all other things being equal) will result in a different sound than a lower ESR cap.

 

[Dr. Morbius]

I'm not sure I understand when people mention about designers 'voicing' the speakers using specific capacitors. Is this true, or just some folklore that keeps getting repeated over and over? I tend to believe it's the latter.

Has anyone actually talked with a designer who claims to have 'voiced' a speaker using a specific type and brand capacitor? Or are they just assuming this was the case?

My thoughts are the "voicing" is in the capacitor's value, dissipation factor and tolerance.

 

[tensleep]

I have often wondered if, after replacing the capacitors in my Bozaks, I should regauss the magnets in the drivers. Changing the capacitors to Dayton polypropylene and slightly modifying the crossover (added a resistor to impedance match) did improve the sound to me. I do think that returning the magnetism to specification could only help as well, but it could very well be cost prohibitive. Bracing the cabinet better and installing a curtain to cancel the back-wave, as originally designed by Rudy Bozak, would probably be money better spent. One thing is for sure - these speakers do sound great, but they are limited by the driver technology that was available at that time, and to try to get them to perform beyond that is really a waste of time and money.

For the sake of the argument here, the polypropylenes were cheap, readily available and had been used successfully in this exact circuit in recent history. In looking over how Mr. Bozak designed and built his systems, I don't think he would have found fault with that.

 

[JimPA]

Capacitors are a conglomeration of linear and non linear resistances and capacitances.

 

[allsmith]

Dangit! Im getting ready to put in a cap order for my epicures and have been debating over if i use poly's will it change the voicing or not, and i had pretty much made up my mind to use poly's, but know after reading this I'm not so sure again! Thanks guys! . Now im just a noob and go by what i read here on AK, but i did talk to a speaker designer that worked for a big speaker company back in the day and he said they most likely used NPE'S because of price. And when i asked him about polys changing the voicing he said "huh" No. But thats just one mans opinion i quess. I still think im going to go with polys since I've always believed in the saying " you get what you pay for" and i cringe at putting a 60 cent cap in a nice pair of speakers when better are available. Not that I'm gonna buy some crazy expensive film and foils, but just some nice metalized polys. I've never heard my speakers before so i will have no idea if it changed there voicing or not, but i think my speakers are worth the upgrade to spend an extra 50 bucks on them . But im just a noob, and have no idea what I'm talking about Lol

 

[tubed]

Anecdotally I have, just for curiousity and on more than a couple occasions, replaced old tiny 12uf original electrolytic caps with on-hand, used mylars on midrange drivers and the improvement was more than subtle.

 

[OSIC212]

I'm not sure I understand when people mention about designers 'voicing' the speakers using specific capacitors. Is this true, or just some folklore that keeps getting repeated over and over? I tend to believe it's the latter.Has anyone actually talked with a designer who claims to have 'voiced' a speaker using a specific type and brand capacitor? Or are they just assuming this was the case?

Other than maybe super high end manufacturers, I'm thinking the designers designed crossovers using what was budgeted for, that being, electrolytics. I don't buy that they insisted on a certain brand, but probably what they got the best price on. And if that supply dried up they'd use a similar product from another manufacturer as long as it met basic specifications.

You hit the nail on the head. During production runs, when a given part has a price increase or supply diminishes it is replaced with a comparable value one.

We all know the line of "specs may change as we are constantly improving our product" The Corporate world of today places profits first, at least for the last twenty or thirty years. Prior to that the above quotation could really mean something.

 

[allsmith]

My thoughts are the "voicing" is in the capacitor's value, dissipation factor and tolerance.

They guy i talked to pretty much said the same thing, and i do now remember him talking about dissipation factor, but i cant remember what he said about it now, as it was a bit over my head and i have been around too many paint fumes over the yrs

 

[tiga]

For what it's worth I put a dayton electrolytic with a film bypass in my EPI 100M's and they are fantastic.

Dangit! Im getting ready to put in a cap order for my epicures and have been debating over if i use poly's will it change the voicing or not, and i had pretty much made up my mind to use poly's, but know after reading this I'm not so sure again! Thanks guys! . Now im just a noob and go by what i read here on AK, but i did talk to a speaker designer that worked for a big speaker company back in the day and he said they most likely used NPE'S because of price. And when i asked him about polys changing the voicing he said "huh" No. But thats just one mans opinion i quess. I still think im going to go with polys since I've always believed in the saying " you get what you pay for" and i cringe at putting a 60 cent cap in a nice pair of speakers when better are available. Not that I'm gonna buy some crazy expensive film and foils, but just some nice metalized polys. I've never heard my speakers before so i will have no idea if it changed there voicing or not, but i think my speakers are worth the upgrade to spend an extra 50 bucks on them . But im just a noob, and have no idea what I'm talking about Lol

 

[allsmith]

For what it's worth I put a dayton electrolytic with a film bypass in my EPI 100M's and they are fantastic.

I have heard about using a bypass cap,and i wonder since ken mentioned that shunt caps are just as important as caps in the signal path that bypassing the large npe shunt caps would be a good idea and upgrade,and save big money:scratch2:

 

[dc270]

I have chose to become more responsible about the cap isse at large. Now when I reccomend caps for replacement it is usually those 'lytics reaching 20 years old. I advise the OP of BOTH options and the respective nuts & bolts of each. To say that replacement polys are the end all is not fair or accurate!
DC

 

[kconnor]

Partial quote:

Just to prove things out I ran down to Radio Shack and got a cheapy electrolytic, popped it in, and the tweeter worked. Later when I went to rework the crossovers , I used Solens purchased from parts express. So ultimately I was able to compare the original oil capacitor from the 'good' Klipschorn, a cheap electrolytic, and a Solen. Frankly, I couldn't tell the difference in sound.

I agree with you. I've changed eletrolytics to film in three or four speaker systems with the intent of improving the sound and was never able to tell the difference after the swap.
Now, I do it as a matter of maintenance with old speakers, removing aged electrolytics replacing them with film when the price is right.
I was somewhat taken aback to see Bennic electrolyic caps in the crossovers of a pair of respected B&W speakers I bought once. That made me think can electrolytics be all that bad?

 

[michiganpat]

I have 2 pair of AR18's...1 pair I did with ERSE electrolytics, the other with solen poly's...

frankly couldn't hear the difference. the polys might be a touch brighter due to lower ESR not attenuating the tweeter as much, but you're talking about what, 1/4 ohm attenuation?

when I redid my smaller advents I used NPE's....

stuff I know I want to keep and don't want to mess with down the road I'll use polys....have solen polys for my AR2ax....even if I don't keep them, the upgrade should pay for itself in the resale market....

 

[Oerets]

I've opened up some nice sounding and expensive speakers only to find electro's in there doing the work. The last was a pair of B&W's. Sure there probably is a benefit but can a person really tell?

I will normally replace with what came out of them.



Barney