Why re-cap speakers?

[guest139]

Audio has been my hobby for over 30 years and I always read about someone re-capping their speakers. I’ve never understood why people replace capacitors without even testing to see if they are even out of spec. To me logic dictates that if a capacitor is not leaking, bulging, or has not exploded and it measures within spec that there’s no point in replacing it regardless of its age. I mean if it’s good it’s good so why fix something that isn’t broken? It seems to me that a lot of people will recap a speaker and then when they listen to it afterward will claim that the speaker now sounds better. But if you don’t perform an A/B comparison then how can you compare before and after when out of all of our senses our hearing has the shortest memory? I can understand changing out a capacitor in something like a Dynaco A-25 that only has one cap for the tweeter for a better quality/tighter tolerance capacitor. But to totally re-engineer a 3 or 4-way 12 or 18dB/octave slope passive crossover and then say it sounds better without a before and after frequency response graph seems pointless. I’m not saying that a frequency response graph tells the whole story of how a speaker sounds but at least you can see where some changes in response were made. I think after someone spends the money recapping a speaker they convince themselves that it sounds better in order to justify all the time, money, and effort spent. Now I’m not saying that EVERYONE that recaps speakers is wasting their time and money. But I think that the average audio hobbyist discovers “re-capping” and then they want to do that to every speaker they get their hands on in the future. Now a vintage receiver I can understand re-capping it because the components in there are constantly subjected to a lot more heat. Anyone please feel free to give your input.

 

[homebrew]

Largely agree with the cap replacement. However the older the cap, the closer it is to failure.

Changing a woofer shunt capacitor that's in spec is unlikely to be audible. However, replacing a series tweeter cap with newer film types may result in an audible improvement. But not always, depending on the tweeter. And I've got a little question with the heat issue. Voice coils, resistors, capacitors can be subjected (and subject) to some pretty toasty temps when the volume's up. Just like an amplifier.

 

[HiFi in WYO]

You're opening a cap, er, can of worms. Many threads on this subject here. I'm generally of the opinion if it sounds fine, leave it alone. However, I've recapped a few pairs now and each time it's brought the speakers back to life ... with the same value caps.

In fact one pair, my most prized pair, sounded like an FM station out of tune so I shelved them for a couple of years. Located the caps responsible for the speaker causing the distortion and replaced those. Voila, fuzz is gone now they're what I knew they could be. And the caps tested, at least on my meter, within spec. So there must be more than them just going bad in a electrical sense.

It's a case by case deal for me.

 

[Drugolf]

Hey! I think there are few reasons that just kinda add up to "why not?" Although there are many I have recapped that needed it.

The issue is you cant do any of those measurements without removing them from the circuit so at that point it's often the easy thing to do and replace them. Many would tell you that for the most part the manufacturers typically used lesser quality caps with only the short term considered. Now that speakers are still in the market 30 plus years later there is a good chance the old caps have issues or will soon enough.

It really is as simple as all that.

 

[spark1]

I have the tools to measure capacitance and ESR.

I have found that the capacitors in many popular "vintage"speakers are often quite far from spec. Both ESR and capacitance are often significantly elevated, with no outward signs of failure. In fact, I don't think I've ever found a Temple cap, popular in KLH models, that was in spec!

As for evaluating the difference...I have found it quite informative to compare the recapped speaker to its mate (before recapping it). The integrated amp in my workshop allows for combining both channels into a mono signal, thereby eliminating variations in content between the left and right speaker. Easy way to compare.

As for "re-engineering"; I don't see replacing old capacitors with new of same value as re-engineering...especially if you use like for like (electrolytic for electrolytic, film for film). To me, re-engineering means changing the performance of the crossover from its original design. New caps don't do this, assuming same values as original.

And as for "not fixing something that isn't broken"; if your vehicle has a timing belt, would you have the same opinion? Electrolytic caps degrade with time....even the best of them. This is a well known and well understand characteristic. Certainly you can choose to wait until it degrades to the point where its degradation becomes grossly obvious. Or, you can get ahead of the curve and do it before that point. I prefer the latter, given that even if not grossly obvious, my experience suggests that 30/40/50 year old caps have changed the intended performance of the crossover.

 

[RTally]

Logic has nothing to do with it. Science. Electrolytic capacitors have a limited life. That life is shortened if they are exposed to high temperatures. Generally, caps installed before 1990 have reached their end of life. Some electrolytic caps have a reputation of failing, sometimes catastrophically or explosively, such as the Temple caps (black body, red ends).

I typically recap one speaker at a time and A/B test it with the original, unrecapped. Occasionally, I hear no difference and don't bother recapping the other. That was the case with my Dynaco A-25. Most times, the difference ranges from slight to significant.

I always listen before recapping. If the sound is muffled, sounds like the speaker has a blanket over it, then it needs to be recapped (provided all the drivers are working). If a tweeter is not working, I recap. In every case, the tweeter comes back alive. If it sounds OK, I will recap if it the speaker was made before 1990 and then A/B test.

Measuring caps seems to be a waste of time to me. You need to remove the caps to test. Might just as well put in new caps instead of installing the originals. I do not consider it a waste of money because I use caps that cost something comparable to the value of the speakers. For example, if the speakers are worth $150 or less, Dayton or Audyn caps are fine. No sense in putting in caps that cost more than the speakers are worth.

 

[StimpyWan]

To me, it's not just about meeting specs. Quality matters.

I had a new set of speakers that I recapped. Not sure why, other than the manufacturer stating they were coming out with an "audiophile edition" of my speakers. So, I figured I could recap and improve things too. Out went the old and in with the new. Higher grade electrolytic in for cheap electrolytic, plus I added film and foil bypass caps. Afterwards, a very nice improvement in sound. Detail and resolution increased, and the speakers sounded smoother and more spacious. My wife even commented that they sounded better, and she didn't know what I'd done to them.

 

[Harvestor]

Logic has nothing to do with it. Science. Electrolytic capacitors have a limited life. That life is shortened if they are exposed to high temperatures. Generally, caps installed before 1990 have reached their end of life. Some electrolytic caps have a reputation of failing, sometimes catastrophically or explosively, such as the Temple caps (black body, red ends).

I typically recap one speaker at a time and A/B test it with the original, unrecapped. Occasionally, I hear no difference and don't bother recapping the other. That was the case with my Dynaco A-25. Most times, the difference ranges from slight to significant.

I always listen before recapping. If the sound is muffled, sounds like the speaker has a blanket over it, then it needs to be recapped (provided all the drivers are working). If a tweeter is not working, I recap. In every case, the tweeter comes back alive. If it sounds OK, I will recap if it the speaker was made before 1990 and then A/B test.

Measuring caps seems to be a waste of time to me. You need to remove the caps to test. Might just as well put in new caps instead of installing the originals. I do not consider it a waste of money because I use caps that cost something comparable to the value of the speakers. For example, if the speakers are worth $150 or less, Dayton or Audyn caps are fine. No sense in putting in caps that cost more than the speakers are worth.

OHM Acoustics model H with Audyn caps and one Dayton Cap..
And a Second Set of OHM Acoustics model H Completely Stock with Original Caps and these Sound Better !

 

[Harvestor]

OHM Acoustics model H with New caps Above...

 

[teal'c]

I do it so my Audiophile card doesn't get revoked.
And maybe a little of the science mentioned earlier.

 

[Lavane]

I do it so my Audiophile card doesn't get revoked.
And maybe a little of the science mentioned earlier.

It really does depend on what is in the crossover to begin with. Electrolytics do have a shelf life. If Film caps were used and the type and brand are known to hold up over time I just leave them. I do replace all electrolytics with film though. I don't buy into the whole "If the manufaturer used lytics you should replace with the same" rule though. For mass production lytics were just cheaper and would do the job. Until they dried out.

 

[rickb119]

Located the caps responsible for the speaker causing the distortion and replaced those. Voila, fuzz is gone now they're what I knew they could be. And the caps tested, at least on my meter, within spec. So there must be more than them just going bad in a electrical sense.

Thank you!

I almost started a thread, "Can a capacitor be bad, but measure good?" My reason? I recently thought I had fried one of my KEF 104/2's when I accidentally inserted the tube on my Saga, incorrectly. The Saga was off, the amp was not and I got a loud POP from the right speaker. Shut everything down, inserted tube correctly, powered on and heard some distortion from said speaker, until it quit completely. No sound at all.

Since I already had the Falcon cap kit, I figured this might be a good time to replace them. I checked each cap (Fluke DVM) as I pulled them and they were all within spec. (more or less allowing for age). However, with the new caps installed the speaker now works again.

I really couldn't tell a difference in SQ (old vs new caps) as, prior to the Saga, I was driving them with a less than adequate (for these speakers) 65w receiver. They do shine with more power though.

Other than the above, I've only recapped one set of Norman model 8's. I used Sonicaps and they did improved the SQ. My ADS were made with quality caps and I feel no need to replace them.

Oops! I lied. Just remembered that I also recapped a pair of NHT SuperOne's, with Dayton caps. I preferred the originals as the Daytons make them too bright. For my tinnitus ears anyhow.

 

[spark1]

It really does depend on what is in the crossover to begin with. Electrolytics do have a shelf life. If Film caps were used and the type and brand are known to hold up over time I just leave them. I do replace all electrolytics with film though. I don't buy into the whole "If the manufaturer used lytics you should replace with the same" rule though. For mass production lytics were just cheaper and would do the job. Until they dried out.

For higher end speakers with carefully designed and implemented crossovers, I believe in replacing like for like, or otherwise accounting for lower ESR of film caps.

 

[F1nut]

Audio has been my hobby for over 30 years and I always read about someone re-capping their speakers. I’ve never understood why people replace capacitors without even testing to see if they are even out of spec. To me logic dictates that if a capacitor is not leaking, bulging, or has not exploded and it measures within spec that there’s no point in replacing it regardless of its age. I mean if it’s good it’s good so why fix something that isn’t broken? It seems to me that a lot of people will recap a speaker and then when they listen to it afterward will claim that the speaker now sounds better. But if you don’t perform an A/B comparison then how can you compare before and after when out of all of our senses our hearing has the shortest memory? I can understand changing out a capacitor in something like a Dynaco A-25 that only has one cap for the tweeter for a better quality/tighter tolerance capacitor. But to totally re-engineer a 3 or 4-way 12 or 18dB/octave slope passive crossover and then say it sounds better without a before and after frequency response graph seems pointless. I’m not saying that a frequency response graph tells the whole story of how a speaker sounds but at least you can see where some changes in response were made. I think after someone spends the money recapping a speaker they convince themselves that it sounds better in order to justify all the time, money, and effort spent. Now I’m not saying that EVERYONE that recaps speakers is wasting their time and money. But I think that the average audio hobbyist discovers “re-capping” and then they want to do that to every speaker they get their hands on in the future. Now a vintage receiver I can understand re-capping it because the components in there are constantly subjected to a lot more heat. Anyone please feel free to give your input.

You've been depriving yourself of better sound over the last 30 years.

 

[quiet]

Sometimes there's something I don't like about the sound of a speaker. If it's working I might replace caps with stock to see what it's supposed to sound like. If I still don't like it I may make changes to the crossovers and lining or stuffing. This works particularly well with old speakers such as Fisher. But you need to have a fair understanding of crossovers to predict an outcome. And a LOT of parts on hand. The more you play with them the more you know what direction to take the speaker in. The speaker may have a good box and drivers but lousy innards, (like the Criterion 5XB) or maybe it just needs to be adjusted with a few parts changing.
It's not "just" about repairs.

 

[HiFi in WYO]

Thank you!

I almost started a thread, "Can a capacitor be bad, but measure good?" My reason? I recently thought I had fried one of my KEF 104/2's when I accidentally inserted the tube on my Saga, incorrectly. The Saga was off, the amp was not and I got a loud POP from the right speaker. Shut everything down, inserted tube correctly, powered on and heard some distortion from said speaker, until it quit completely. No sound at all.

Since I already had the Falcon cap kit, I figured this might be a good time to replace them. I checked each cap (Fluke DVM) as I pulled them and they were all within spec. (more or less allowing for age). However, with the new caps installed the speaker now works again. .

This was on my 105.1s. They were recapped with those red and black ones whichI read were known to go haywire over time. Must have.

 

[HiFi in WYO]

For higher end speakers with carefully designed and implemented crossovers, I believe in replacing like for like, or otherwise accounting for lower ESR of film caps.

Works well on relatively primitive crossovers too! Never liked my EV Fours until I replaced the caps. Now they're very lovely speakers.

 

[jobrewer1983]

Audio has been my hobby for over 30 years and I always read about someone re-capping their speakers. I’ve never understood why people replace capacitors without even testing to see if they are even out of spec. To me logic dictates that if a capacitor is not leaking, bulging, or has not exploded and it measures within spec that there’s no point in replacing it regardless of its age. I mean if it’s good it’s good so why fix something that isn’t broken? It seems to me that a lot of people will recap a speaker and then when they listen to it afterward will claim that the speaker now sounds better. But if you don’t perform an A/B comparison then how can you compare before and after when out of all of our senses our hearing has the shortest memory? I can understand changing out a capacitor in something like a Dynaco A-25 that only has one cap for the tweeter for a better quality/tighter tolerance capacitor. But to totally re-engineer a 3 or 4-way 12 or 18dB/octave slope passive crossover and then say it sounds better without a before and after frequency response graph seems pointless. I’m not saying that a frequency response graph tells the whole story of how a speaker sounds but at least you can see where some changes in response were made. I think after someone spends the money recapping a speaker they convince themselves that it sounds better in order to justify all the time, money, and effort spent. Now I’m not saying that EVERYONE that recaps speakers is wasting their time and money. But I think that the average audio hobbyist discovers “re-capping” and then they want to do that to every speaker they get their hands on in the future. Now a vintage receiver I can understand re-capping it because the components in there are constantly subjected to a lot more heat. Anyone please feel free to give your input.

Not trying to be an ass, but I have a few questions.

1. What does 30 years in the hobby have anything to do with anything? (Just poking ya)

2. What caps do you use? (Please don’t respond Dayton)

3. Have you ever recapped speakers yourself and noticed an upgrade in sound?




You had mentioned a singe cap XO.. ^^ JBL L16s ^^ was a single cap, now they are at exact values.



I agree on some of your points but I think you are failing to see that it’s not the just “uF” values that can affect the sound of a driver. You may keep the crossover point the same with similar caps of equal value.

An example/question for you:

If a speaker has a 4.7uf cap for the high pass, what you are saying is if I were to put any old cap that is 4.7uf In and I would get the same sound stage as a top end high grade 4.7uf cap?

I agree most folks don’t test the original caps, some of us do. I do when it comes to JBL a lot of times the paper caps are a good 10-20% out of spec.

I also agree that lots of folks say they don’t notice a difference, then I see they used an equal grade cap as to what was already installed. You won’t notice a sonic upgrade unless you upgrade to a better cap.

 

[guest139]

I have the tools to measure capacitance and ESR.

I have found that the capacitors in many popular "vintage"speakers are often quite far from spec. Both ESR and capacitance are often significantly elevated, with no outward signs of failure. In fact, I don't think I've ever found a Temple cap, popular in KLH models, that was in spec!

As for evaluating the difference...I have found it quite informative to compare the recapped speaker to its mate (before recapping it). The integrated amp in my workshop allows for combining both channels into a mono signal, thereby eliminating variations in content between the left and right speaker. Easy way to compare.

As for "re-engineering"; I don't see replacing old capacitors with new of same value as re-engineering...especially if you use like for like (electrolytic for electrolytic, film for film). To me, re-engineering means changing the performance of the crossover from its original design. New caps don't do this, assuming same values as original.

And as for "not fixing something that isn't broken"; if your vehicle has a timing belt, would you have the same opinion? Electrolytic caps degrade with time....even the best of them. This is a well known and well understand characteristic. Certainly you can choose to wait until it degrades to the point where its degradation becomes grossly obvious. Or, you can get ahead of the curve and do it before that point. I prefer the latter, given that even if not grossly obvious, my experience suggests that 30/40/50 year old caps have changed the intended performance of the crossover.

I have the tools to measure capacitance and ESR.

I have found that the capacitors in many popular "vintage"speakers are often quite far from spec. Both ESR and capacitance are often significantly elevated, with no outward signs of failure. In fact, I don't think I've ever found a Temple cap, popular in KLH models, that was in spec!

As for evaluating the difference...I have found it quite informative to compare the recapped speaker to its mate (before recapping it). The integrated amp in my workshop allows for combining both channels into a mono signal, thereby eliminating variations in content between the left and right speaker. Easy way to compare.

As for "re-engineering"; I don't see replacing old capacitors with new of same value as re-engineering...especially if you use like for like (electrolytic for electrolytic, film for film). To me, re-engineering means changing the performance of the crossover from its original design. New caps don't do this, assuming same values as original.

And as for "not fixing something that isn't broken"; if your vehicle has a timing belt, would you have the same opinion? Electrolytic caps degrade with time....even the best of them. This is a well known and well understand characteristic. Certainly you can choose to wait until it degrades to the point where its degradation becomes grossly obvious. Or, you can get ahead of the curve and do it before that point. I prefer the latter, given that even if not grossly obvious, my experience suggests that 30/40/50 year old caps have changed the intended performance of the crossover.

By re-engineering I did mean completely changing the crossover performance from its original design. I read about people using totally different value capacitors and then they say the speaker sounds much better afterward and I’m thinking, “No. it sounds different than what you got used to.”

 

[quiet]

Sometime a correction is needed to fix a bad speaker voicing. I can't tell you what it is, but I know it when I hear it.
And I never get used to it.