Why Replace Speaker Capacitors

[TheGoldenBoy]

I have an older set of speakers that do not sound as "right" as I remember them-

I was wondering if replacing the capacitors would help this- however, they appear to be very difficult to open up.

Since removing the grille cloth on these speakers would be a lot like work, I was wondering what the specific symptoms of bad capacitors are. It's one thing to say "old capacitors need to be changed" or "if your speaker doesn't sound right, you need to change the capacitor" it's another thing to say "replace your capacitors if your speaker is lacking bass response or the tweeter doesn't work, or..."

 

[malden]

I have only replaced the capacitors on one set of speakers., they were a beautiful pair of Pioneer CS-63DX from the early 1970's. After spending about 40 or 50 bucks on parts and a couple of hours removing the drivers, swapping out capacitors, re-glueing them in place, and putting everything back together, they sounded the same. I then measured the old capacitors and they all tested within spec.

I'm not saying replacing crossover capacitors is a waste of time, but I wouldn't jump to conclusions. There may be some other problem causing your speakers to sound bad.

 

[TheGoldenBoy]

Every part of the signal chain is a link... (duh) and every piece is voiced differently.

I'm not using the same receivers/amplifiers that I used to use with these speakers- and that could well be what's going on.

Then again, I'm also going off memory- when I look up discussion about these speakers there's a common theme about them- so I don't know if I was just used to *that* sound, and now that I'm using different combinations of gear that it's emphasizing *that* sound.

I was hoping there'd be a concensus about what a cap replacement fixes. I understand old caps can leak- but what sound do they make when they leak? Is it an open circuit- or a straight through closed circuit- and what does that sound like?

I'd kind of like it to be a cap thing- then it's replace those and magic. But if it's a "speaker voicing" thing- that's just how they are.

My thought to get into these would be to cut the grille cloth and devise a way to attach new grille cloth- a whole lot of work for something that probably would not look so good, knowing me and my arts and crafts abilities.

 

[N8Nagel]

Classic symptom of bad crossover cap(s) is that the treble will sound rolled off.

I have some speakers with original caps that don't sound bad to my ears, and some to which replacing the originals made a dramatic improvement.

 

[toxcrusadr]

Ditto on the treble. And sometimes an overabundance of midrange. Whether that's real or an auditory result of loss of treble, I don't know.

They can also fail open so a driver doesn't play at all.

So what speakers are these? Maybe we would have some insight on this particular model based on its age or even a pic of the crossover off the web...

 

[BobHol]

Instead of taking off the grill cloth check to see if you can remove the rear panel.

 

[likebike23]

Hey Dave, how've you been? My limited experience has been that one pair of speakers lost the tweeters due to bad capacitors. On my ADS 520's I need to recap them due to muddy bass response. The woofer on those uses a capacitor. So, there can be differing symptoms depending on how the crossover is designed.

 

[trinhsman]

I had capacitors replaced on my old Snell speakers. They were about 25 years old. The change resulted in a much more clear and detailed sound. The wife approved, so I know it was for the better.

 

[StimpyWan]

I recapped a new set of speakers (Monsoon FPF-1000) with Bennic NPE's, bypassed with Dayton Film & Foil capacitors. This inexpensive recap sounded much better. Clearer, with more presence. Smoother too. Even my wife noticed the difference.

I'm also recapping a set of 35 year old Acoustic Research AR90 speakers. I though they still sounded good, even though they were older now, until after the recap. I compared a recapped set of crossovers to the other stock speaker. Just a dome mid on the new crossover, compared to the normal speaker. A night and day difference. Clearer, cleaner, less distortion. That single mid even sounded more wide range, with better midrange and treble response, than both the mids and tweeter in the other speaker. Well worth the cost (Mundorf caps), and time. I'd recommend it. It doesn't have to cost much to do either. My Monsoon recap didn't.

 

[maxhifi]

When the capacitors were bad in my Realistic Nova 7B, the symptom was weak highs (increased ESR), and a hole in the midrange (raised crossover due to lowered capacitance). New capacitors brought them back to life. Not totally trusting my ears, I verified the results with before and after measurements.

Other results may be less dramatic. The only way to really know for sure, is get a calibrated mic and check the frequency response of the speaker system for anomalies. Or alternatively to remove the capacitors and check them for value, leakage, and ESR with a capacitor tester. Lacking those facilities just buy new caps. I have been happy with replacing like with like, i.e. nonpolar electrolytics with new ones. Others prefer to "upgrade", but be aware it may change the way the speaker sounds from original.

 

[Collin1141]

What make and model are your speakers?

Some caps will fail open and you will outright lose a driver, this is very common in older speakers that used electrolytic bi-polars
The really ancient wax types will do the same
Then there's the combination value types, those black things with red ends that KLH liked, they can and do literally explode after aging 45-50 years or so
Then there are original caps that measure on spec, like some of the caps that Klipsch used, that replacing with a good polypropylene will just make sound better
Talking old Klipsch in between the paper in oil times and today, 1970s-1980s
Klipsch used good quality caps by the way but they were often off the self industrial types like motor start and such
Nothing wrong with them at all functionally and every one I have ever replaced still measured good, it was what was available when they were built, the new caps just improved the sound for me
Cap technology has improved dramatically over the last 50 years and I'm not talking about magic caps or boutique stuff, just the materials science has improved
The caps that a manufacturer uses will often be determined by the bean counters, in a lot of instances you can improve upon what's in your speakers but I would evaluate that on a case by case basis
I have had two pairs of old German speakers (Telefunken) from the late 50s early 60s and both had dried out and failed open bi-polars resulting in a dead tweeter

 

[msh1999]

skipped the comment above but to put this simply...

some speakers need replacing and some dont.
how you know when to replace? when they sound bad and you know from they should sound better then they currently do.

for example: replaced capacitor in speakers from 83`~, the sound was all good and it was clear the old cap was not good.
and i had KLH model 6, which maybe needed replacing but they sounded so good that i didnt care so never replaced the caps.

 

[Collin1141]

Speaker caps are like your wife
You never know how old she looks now until you dig up an old picture from 30 years ago
Or your own face in the mirror
It happens slow and you may not notice it
Same as a TV's picture getting old

 

[Collin1141]

Every part of the signal chain is a link... (duh) and every piece is voiced differently.

I'm not using the same receivers/amplifiers that I used to use with these speakers- and that could well be what's going on.

Then again, I'm also going off memory- when I look up discussion about these speakers there's a common theme about them- so I don't know if I was just used to *that* sound, and now that I'm using different combinations of gear that it's emphasizing *that* sound.

I was hoping there'd be a concensus about what a cap replacement fixes. I understand old caps can leak- but what sound do they make when they leak? Is it an open circuit- or a straight through closed circuit- and what does that sound like?

I'd kind of like it to be a cap thing- then it's replace those and magic. But if it's a "speaker voicing" thing- that's just how they are.

My thought to get into these would be to cut the grille cloth and devise a way to attach new grille cloth- a whole lot of work for something that probably would not look so good, knowing me and my arts and crafts abilities.

So what are the speakers you're having doubts about?
I'm truly interested in knowing if you don't mind
You can't ask a question like the one you did and not reveal what it is we're talking about
Sure, you'll always get the noise, but you may also get some feedback from someone who is actually familiar with what you own, maybe they even own or have owned the same speakers you have and have actually re-capped theirs

 

[loudnoises]

From my experience, not all caps are created equal, and what they do with age varies. Here's some useless information:

Some caps simply die after a time (KLH model Six, caps were just dead, open).
Some caps go out of spec (fisher branded ritcheys, but not the normal ritcheys I've seen).
Some caps physically break (ritchey, i'm looking at you) and fall off the crossovers.
Some caps test just fine, but replacing one and comparing old vs new side-by-side (the 80uf in DQ-10s) the change was unmistakable.
Electrolytics die sooner, films last a long time. Oil caps last forever it seems.
Film are bigger than lytic. Sometimes MUCH bigger.
Replacing an old lytic with a new film should produce a notable change.
Replacing good old film with new film is a waste of money.
$200 in boutiqe caps + white van speakers = white van speakers.
Hot glue vs RTV: the next "wire" thread. Both work. Don't cook your caps in glue, don't seal RTV vapors inside your cabinet.
Old cap values are often unobtanium, or stupid expensive and only available on the third sunday of every 7th month, if the gopher sees his aunt on a tuesday (but not Monday!), coming out of bulgaria, shipped by pack mule. Combining values is very common and accepted practice,

Where are my pants...

 

[NAD80]

Great post loudnoises. Had to recap my Mission 737R's. Brought back the high end of the tweeters. Seen pics of those exploding red end caps.

 

[Collin1141]

I recently did a pair of Type E-2 networks for a friend

Klipsch had used a very well made cap for the squawker and the tweeter, a Matsushita 2.0uF 180V 5% industrial looking axial film type, probably mylar, and a nice 33uF 100V Nippon Chemi-Con 10% electrolytic bi-polar for the trash can in the woofer circuit
Good honest parts, not crap like they use so much today, Classic P.W.K.

When I removed the three devices from each network and checked them they were all spot on, even the wet cap. I mean SPOT on, not just within the 5% for the films. I told and showed this to my friend, but he had made up his mind he wanted his speakers re-capped so I did it for him

Nothing fancy, standard fare from Part Express. I also by-passed them with .01uF film and foils, à la JBL, which I always do

The results? I was impressed. Not going to say stupid crap like "amazing" or "night and day difference" or "we were blown away"
But I will say that by swapping out those three caps and replacing them with the polypropylenes his speakers were cleaner, clearer and just smoother on the edges sounding than I had ever heard them before. There was a lot more inner detail on top with much less of that kind of shouty sound that Klipsch can give you, sometimes, on certain recordings especially when you play them loud. Just a more refined, effortless sounding presentation and the speakers sounded very good to begin with. A very definite improvement

Proved well worth doing and only cost a few dollars. As for the 33uF electrolytic, it was replaced with a nice looking 10% generic I think they charged me a whopping 98 cents for. I by-passed that one as well, just for the hell of it

 

[GlenGC]

there is no clear guideline to explain how to know whether caps need replacement or not.. even for a trained ear, sometimes it's the question "is this the way this speaker is, or is there an issue with the speaker"
you need a solid reference point to begin with.. since our brains don't record waw files and frequency spectrum screen shots, even our own speakers that's been with us for decades stray from the original spectrum and we don't even notice it until issue becomes too evident..

so.. when you say, speakers don't sound as good as i remember.. it's a hard problem to resolve.. many things can happen to a speaker that make them sound different or less good over the years, sometimes this is just natural ageing and sometimes its a problem growing

in my experience capacitor problems are easier to notice at higher volume levels (dont blow your speakers testing this) yet again, this goes back to the reference point.. most speakers begin distorting as the volume increases, so to evaluate the difference between low and high, and identify if this is a natural distortion or cap shifting value is again for a trained ear..
bad caps stray from their original value, and i think (i have no proof .. it's just a theory) they shift from this value further when stressed by more voltage.

i had a B&W where the tweeter began chirping around at 30-40 watts or more load, but sounded ok at low power, issue was the capacitor. even though the old cap measured near to it's original value 4.9uf against 4.7
replacing it fixed the issue.. this is where my higher power higher shift theory comes from.or maybe it was just the tweeter suspension causing chirping due to frequency altered at higher volume .. not about the voltage to the cap. maybe both

if not too much trouble.. go ahead and replace them.. with quality capacitors, it won't do any harm.. if no improvement at all, take it as an investment for longer life for your speakers.

 

[bowtie427ss]

n my experience capacitor problems are easier to notice at higher volume levels (dont blow your speakers testing this) yet again, this goes back to the reference point.. most speakers begin distorting as the volume increases, so to evaluate the difference between low and high, and identify if this is a natural distortion or cap shifting value is again for a trained ear..
bad caps stray from their original value, and i think (i have no proof .. it's just a theory) they shift from this value further when stressed by more voltage.

Very astute observations.

To be tested properly, a capacitor needs to be under a working load or simulation thereof. 99.8% of the members on this forum, or most any forum for that matter, do not have the facilities to do this. Folks need to understand that buying a 29 dollar LCR meter does not make them experts on capacitor health and performance. A lot of folks are going to get a good value reading on their 30+ year old 'lytics, and don't understand that it is in no way an indication of what that cap is doing with a working voltage source on one end and a working load on the other.

 

[StimpyWan]

...but he had made up his mind he wanted his speakers re-capped so I did it for him

Nothing fancy, standard fare from Part Express....The results? I was impressed. Not going to say stupid crap like "amazing" or "night and day difference" or "we were blown away"

I'm also recapping a set of 35 year old Acoustic Research AR90 speakers...A night and day difference. Clearer, cleaner, less distortion....

Oh well, I guess I embarrassed myself, with my critique of my recap...!