Capacitors

Sorry, I forgot ...
I have to replace three bi-polar electrolytics of the medium-high crossover board of my B&W 801 s3 speakers.

Thanks!

Yes. As long as you know what you are doing and you’re aware of the possible risk of changing the frequency balance.
Look at this shoot-off between caps.

And another capacitor test.

Those links are all to film cap comparison. If you have the ability to put in a film cap, it can be much better. However, film caps are significantly larger in physical size and may not fit for the uf value you may need. So, electrolytic capacitors may need to be used in those specific scenarios. Also, this electrolytic capacitor could very well be for a notch filter circuit, which does not affect sound quality as much as other capacitors directly in the signal line.

I usually go for nichicon bipolar caps for speaker crossovers if I need them.

But the OP asked for "other not-polarized." Wouldn't they have said with other "bi-polar electrolytics?"
But good point on the size.

Depends how old, and where.

In series = Safe
Going to ground = Dangerous
Old = High ESR
Newer = Low ESR


If you are replacing a series cap, relatively ( < 10 years) new, you are fine.

If the cap is old, it probably has higher ESR, and that should be taken into account, but in series it's not much of a problem.
The problem is in shunts ( 2nd component in low pass)  where loosing a couple of ohms can dump the speaker impedance to 2 Ohms, and cause you to loose amplifier output.

Maybe not. The crossover design probably required the high capacitance of the polarized cap and the designer took into account the high ESR into the overall impedance. Replacing that cap with a lower ESR film may throw things out of balance and may require a series resistor.

Hi, I report the data of the crossover scheme:

in high pass band
bennic 26uf - 7 watts in series;
bennic 8uf - 7 watts in parallel;

in low pass
bennic 85uf - 7 watts in parallel.

I proceed step by step to avoid unbalancing the speaker.
Thank you all for the detailed info.

I forgot ..

the speakers date from 1992

Thanks!

I have used these and they sound good. These should work as long as they fit.
https://www.partsconnexion.com/capacitors-film-claritycap-tc600-series.html

Of course, ideally you measure the ESR of each cap before replacing.

You can do this with a DATS unit or using Room EQ Wizard with a custom jig.

The 26 uF in the high pass doesn't make a lot of sense though. Are you sure?

@erik_squires https://www.diyaudio.com/forums/attachments/multi-way/49444d1125082544-amp-801-matrix-s3-crossover-s...

@noromance

Oh, OK, this makes more sense.  The 26 uF is on the mid range.

Be VERY careful replacing the 8uF that is in parallel on the mid. I'd need to do a full analysis, but if that has 2 Ohms or so of ESR, you don't want to remove it.

Best,

E

Hi,

yes, the capacitors 8 and 26uf is on the mid range.

Thanks!