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RE: capacitors

Posted by seancuster71@gmail.com (P) on November 22, 2024 at 00:29:09

In Reply to: RE: capacitors posted by Leo loves music on November 18, 2024 at 19:15:36:

Audiophiles removed those protection circuits so did B&W on the 801 S3 the S3 has no protection circuit. And the electrolytic capacitors do not have to be in the signal path to degrade the sound. The capacitors that are in parallel or not in the signal path greatly affect the sound and you have multiple electrolytic capacitors in parallel in your 801's crossover.

Here is why that is so important you won't see a tolerance under 5% +/- on an electrolytic cap so an 8uf capacitor with a 5% +/- tolerance could be from 7.6uf to 8.4uf. But over time electrolytics lose capacitance and gain resistance or ESR equivalent series resistance.

An electrolytic capacitor can lose 20% of its capacitance over time so your 25-year-old capacitors need to be replaced. So, if an 8uf capacitor lost 20% of its capacitance it would be a 6.4uf that is huge. So your woofer crosses over at 380 HZ losing 20% of capacitance on the Parallel capacitors could be as much as a couple hundred hertz difference so your actual crossover point could be as high as 580 Hertz. And the ESR equivalent series resistance key word resistance increases so what happens when we increase resistance, we lose volume so not only are the electrolytic capacitors faded capacitance changing your frequency response they are slightly lowering the driver's volume.

So, you have the schematic that is great now you can make better crossovers. Higher quality caps and resistors and you could even use inductors that are a lower AWG for example an 18 AWG 5MH inductor has 0.50 OHM resistance a 14 AWG 5MH inductor has 0.09 OHM resistance. The less resistance on your woofer the better bass response. The more resistance the less dampening factor your amplifier has, and dampening factor is your amp's ability to control the speakers cone especially around the crossover point that is why you see really high-end speakers always using large gauge inductors

Do yourself a favor and change those electrolytics get some good, metalized film capacitors with a modern tolerance of 2% it does not cost much can be done in an afternoon and you won't regret it.

It is important to understand what those caps not in the signal path do they are controlling the frequency response. On a woofer an inductor in series is a first order crossover 6db per octave slope add a cap in parallel after the inductor you now have a 2nd order crossover 12db per octave slope these components are removing high frequencies. The larger value inductor & capacitor the more high frequencies removed the lower the values the less high frequency removed so if your capacitor has lost 15 to 20 percent capacitance it is now removing less high frequency which means your woofer is now playing well past it's 380 HZ that B&W intended.

Also B&W used some cheap components in their crossovers. Like the electrolytic capacitors are bennic very cheap i think they have a huge tolerance range like 10% or 12% =/- that's bad they should have used Mundorf and instead. And shock!! they are not using polypropylene capacitors in the signal path they used polyester capacitors, and they suck for crossovers. Polypropylene has a lower dielectric loss than polyester and that is way better for high frequencies they use cheap sand cast wire wound resistors they should have used non inductive wire wound like Mills so I am sure all the inductors are probably 18 or 20 AWG. This is why so many people upgraded these crossovers back in the day I can only imagine how bad those bennic caps measure after 25 years.

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Kimber Kable

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