Capacitor damaged in speaker crossover

[admin]

I opened up the crossover for my Magnepan 20.1's and noticed that one of the caps seemed to have the outer housing damaged. I have not noticed any sound degradation but I think I'm going to replace it for safety sake. I figured I would replace it with the same exact brand/model so that I don't have to change the other speaker's crossover and keep the sound uniform.

I found the exact replacement on the Solen website: https://solen.ca/products/capacitors/fa ... lene-film/

However, it's a Canadian company and I was hoping to find it from a seller in the US. I've ordered from parts express before and they seem to have an alternative which is the same brand has the same capacitance but rated at higher voltage: https://www.parts-express.com/Solen-12u ... quantity=1

I can't seem to find it with another reputable US dealer (which would be my preference as the shipping would most likely be faster and I don't want my setup to be down longer than it has to). As far as I understand, you can substitute higher voltage rated caps for lower spec ones so I should be ok with the 400V rated ones.

I have these scenarios to choose from:
1) Buy from parts express and just substitute it for the 400V version.
2) Buy from parts express but buy two and change it in each crossover in case the newer 400V model has different audio properties than the older 250V version.
3) Buy from the Canadian supplier for the same 250V model (either to replace one or both channel crossovers) to have the specs unchanged but have my system down for a longer period.

Would like to hear your thoughts.

[Q3Di]

I would get exact same specs (I have no knowledge in higher/lower voltage) or check with the manufacture if the alternative will work and won't affect the sound.
Since your system is still running now; so it is ok to wait a bit for delivery. I don't think it would take longer than a week to ship from Canada.

[admin]

You're right, probably better to buy the same ones again. Bought directly from Canada and it only costs $23 USD total. Hopefully the shipping won't take too long.

[AnotherJohnson]

You never want to go lower in voltage because that choice will shorten the service life.

Regarding the capacitance value, capacitors are a reactive component with a complex impedance. The crossover frequency will be affected by the choice you make. I would stick with the original design values.

Capacitors pass high frequencies and block low frequencies, with the transition region dependent on the capacitance.

The other crossover reactance is the coil. Coils pass low frequencies and block high frequencies. Again, the transition region is dependent on the inductance.

[admin]

I've seen many examples of caps failing and bulging. I've fixed this in my audio audio/video equipment and computer equipment numerous times. However, I have never seen anything like this where it looks like the wall of the cap has disintegrated. There is no bulging. I'm wondering if this is how it was installed, but I can't imagine somebody would put an obviously damaged $10 component into a $+10,000 speaker?

[AnotherJohnson]

Bulging or blistering is usually a failure mode for electrolytic caps. I think these are polypropylene. Polypropylene caps are usually long lived, rivaling Teflon.

I’m not sure how this cap failed.

That the failure appears to not have affected the sound is another enigma, although maybe the capacitance hasn’t changed much.

Could a mouse have gotten in and chewed it? We’ve seen mice chew electrical insulation in motorcycles. Maybe the Maggies are tasty too.

[admin]

It's a mystery to me as well. No chance of a mouse as this is in the crossover box which is completely sealed. Not even vent holes.

[AnotherJohnson]

http://cds.cern.ch/record/2038610/files ... .01540.pdf

This paper presents a set of failure modes for this type of cap and their causes.

It might be smart to replace them all. There maybe be no noticeable sound change because they’ve all aged out.

[admin]

Interesting paper. I had ordered the replacements yesterday (for both channels). If I notice any sonic improvement I will consider replacing all the caps in the crossover. I'll keep you guys updated.

[Q3Di]

Replacing all the caps? It would be a fun project. I don't have expertise to repair/rebuild electronic equipment. But it is fun to learn

[admin]

Luckily all the caps in the crossover are easily accessible so it actually wouldn't be that hard to do. Again, I want to see if replacing the cap give some really noticeable acoustic property over the other channel. If so, I may just do another order and replace everything. I think I'll start with the one cap for now.

[AnotherJohnson]

I’m sure it will be fun to experiment... but if they’ve all aged out, replacing one won’t have the dramatic effect of changing them all.

Same with the PV12. One gets used to the degradation over time and one becomes accustomed to the presentation.

If I’ve got 6 weak spark plugs in my Gold Wing and I replace 1 of them, I will probably notice a slight improvement... or not, depending on how bad the others are. They may all look a nice tan color, but they may still be weak.

If I replace all six weak plugs, I will notice the improvement easily.

It is the same with the PV12 and the Maggies.

You won’t know what you’re missing until you’ve bitten the bullet and taken care of what is honestly routine, unavoidable maintenance.

Polypropylene and polystyrene caps age out in 10 to 20 years. They do not show it by bulging or blistering. Teflon caps typically last longer, maybe as long as 40 year's. Electrolytic caps are more like 10 year life components. They do blister, bulge, pop, and leak ... but they already sucked before this visible evidence of failure manifested itself.

It is cheap to follow “if it ain’t broke, don’t fix it.” But that is not the road to audio nirvana.

I’ve been down both roads. I know where they go. Either destination can be a happy place ... but they’re not the same place.

[admin]

I agree that the optimal solution would be to replace all the caps every 10 years. I think for the speakers that may be a project I undertake in the near future. As I mentioned before, the crossovers are rather easy to access and work on so that may be an easier project. I'm going to start with the clearly damaged cap as I feel that is a priority to get my system in working order.

As for the PV12. I'm a little hesitant in putting a lot of time and money into this unit as right now it's the weakest link in my system. I may just want to approach the situation with an upgrade to a better/newer CJ preamp. I like buying on the used market as I've had a lot of luck with finding big discounts. My ART amps I was able to get for less than 1/5th MSRP and it was local purchase. If I can find a similar deal on a high end CJ preamp, that would be the best and most feasible approach. I have to keep alert and search the classifieds on a regular basis.

[admin]

Well, after (what felt like) a long wait due to shipping from Canada, I got the replacement cap. Replaced the bad cap in the crossover and I am happy to report the speaker sounds wonderful. I want to tell myself that it sounds even better but I think that is just placebo effect and the fact that my system was out of commission for nearly two weeks. Going two weeks without experiencing audio nirvana is hard and makes the return that much sweeter.

The replacement was rather easy. Just two quick solder points. The crossover gives fairly good access to the components so I actually did the replacement in my listening room and didn't have to remove the entire crossover assembly. Overall, a simple fix with the hardest part being waiting for shipping on the component. I think Amazon's 1-2 day typical shipping time has spoiled me!

Below you can see the comparison of the old and new cap. When I removed it and compared, it actually does look like there was some early bulging going on that you can see on the sides.

[AnotherJohnson]

That's a serious cap failure, as it also appeared in the first photos a couple of weeks ago.

It is not your imagination that it sounds better. Congratulations on the success!!

Seriously, you will not know what you're missing until you recap both crossovers, and take a serious stab at sorting out the PV12.

All this stuff sounds just fine ... except in comparison to what's better. Edison was able to fool people into thinking they were listening to an orchestra with his little cylinders. Psychoacoustics is real.

So ... if you really want to experience audio nirvana, take care of these obviously aged out parts. Aging out is a real issue for caps. If you don't believe it from me, talk to JF. Just because they've aged out doesn't mean you can't still enjoy them ... at least until they are humming or dead ... but it does mean that you've got some seriously modestly priced improvements to do that will reward you for your efforts.

[admin]

When I opened up the crossover I was looking at it from the perspective of what it would take to recap the entire setup. It would not be a "huge" project but it would take some time, effort, and a little bit of money to replace everything. I think this is something that I would like to do. My current priorities in improving the system are:

1) Find a replacement to my PV12. I could recap everything there but I don't think I will achieve the same performance as simply going to a higher end and newer CJ preamp. Why put in the money and effort when I plan to replace the unit in a short time anyway?

2) Recap the magnepan 20.1's crossovers completely. This would be a less expensive endeavor but more time consuming.

With my recent purchase of the ART amps, I am trying to be a little cost conscious as the moment. I would really like to find a "bargain" on a used CJ preamp. I got very lucky with the ART's and if I can replicate a similar deal for a preamp, that would be ideal. I've also been extremely busy in my "non-audio life". I work in healthcare and my schedule has been all over the place due to covid. My wife is also having surgery next week with another scheduled about a month later so that is currently taking most of my attention. I hope that by this summer things will calm down a little and I can focus more back on the audio.

[roberto]

Chicos,

I am very picky with caps. Usually the coupling caps are the culprit when you have a bad voltages in a certain stage, preamps or power amps. Caps could measure right, but are bad. The only way is replacing them. Recently my dB meter had a failure with the monitor amp. A bad capacitor was the problem. 10uF @ 25V. That simple cap made a big problem...no monitor at all.

Caps are very important and we all know that. It is so good to know that you did a good thing on your speakers Admin. And do trust your ears! They are telling a big truth. Capacitors do a big performance in the circuit path. They do make a big difference with their quality too.

Good for you Admin. Now, with your new toys mono blocks and new crossover caps in the speakers, that sound must be marvellous.

Happy listening!

[AnotherJohnson]

I
I've also been extremely busy in my "non-audio life". I work in healthcare and my schedule has been all over the place due to covid. My wife is also having surgery next week with another scheduled about a month later so that is currently taking most of my attention. I hope that by this summer things will calm down a little and I can focus more back on the audio.

Family is most important. All the audio stuff is “in the noise level” of a busy life.

Take my comments with large grains of salt. No human knows what’s best for you better than you.

Best wishes to your wife as she goes through her procedure and recovery.

[roberto]

Admin,

I do know for sure that God already had designated an army of Angels for her surgery protection. My prayers will be for both of you too!

A big hug from Costa Rica,
Roberto.