Replacing bipolair electrolytics with MKT in speakerfilters?

[justanalogue]

Hello,

I was wondering if I could replace my old bipolair elko's with MT or MKP capacitors.
Been searching the web for a while and didn't found an answer yet except some audiophoolery stuff...
Speakers are B&W 802-80 from 1983.

Thanks in advance.

Best regards,

Willem.

 

[abbey road d enfer]

Hello,

I was wondering if I could replace my old bipolair elko's with MT or MKP capacitors.
Been searching the web for a while and didn't found an answer yet except some audiophoolery stuff...
Speakers are B&W 802-80 from 1983.

Thanks in advance.

Best regards,

Willem.

It can only be better. Bipolar elcaps tend to suffer the same as all electrolytics: losing their value and becoming leaky. But film capacitors are much more expensive than bipolar elcaps, value for value. I recently purchased 50 x 190uF MKP's at nearly 20 Euros apiece...

 

[playboss]

"I recently purchased 50 x 190uF MKP's at nearly 20 Euros apiece..."

wth, these 6.8 here are already huge!

 

[justanalogue]

Hello,

I was wondering if I could replace my old bipolair elko's with MT or MKP capacitors.
Been searching the web for a while and didn't found an answer yet except some audiophoolery stuff...
Speakers are B&W 802-80 from 1983.

Thanks in advance.

Best regards,

Willem.

It can only be better. Bipolar elcaps tend to suffer the same as all electrolytics: losing their value and becoming leaky. But film capacitors are much more expensive than bipolar elcaps, value for value. I recently purchased 50 x 190uF MKP's at nearly 20 Euros apiece...

Thanks a lot but were do you need those caps for?Speakers?

Just curious.

Best regards,

Willem.

 

[abbey road d enfer]

Hello,

I was wondering if I could replace my old bipolair elko's with MT or MKP capacitors.
Been searching the web for a while and didn't found an answer yet except some audiophoolery stuff...
Speakers are B&W 802-80 from 1983.

Thanks in advance.

Best regards,

Willem.

It can only be better. Bipolar elcaps tend to suffer the same as all electrolytics: losing their value and becoming leaky. But film capacitors are much more expensive than bipolar elcaps, value for value. I recently purchased 50 x 190uF MKP's at nearly 20 Euros apiece...

Thanks a lot but were do you need those caps for?Speakers?

Just curious.

Best regards,

Willem.

Yes, I use that in conjunction with an inductor to notch an unwanted resonance; and it's BIG!

 

[playboss]

welll, you better glue it right then

 

[olafmatt]

B&W advises against replacing the bipolar electrolytics with film caps. They say they included the series resistance of the electrolytics into the value calculation for the other parts. So if you put in better caps you have to add small resistors in series.

Olaf

 

[justanalogue]

Hello Olaf,

thanks for this, thought about it but they are 25 years old so they must been dry.
Replace them with quality bipolar's?

Thanks in advance,

Willem.

 

[olafmatt]

Replace them with quality bipolar's?

Yes, but ideal would be find some of the same make and type, or at least with similar resistance values.

Managed to find an online copy of the B&W statement I was remembering: http://home.netvigator.com/~goneill/bwfaqn.htm

Olaf

 

[justanalogue]

Thanks for this, have read the other article a couple of times but never saw this.
Time for reconsidering and more, more research.
Just want to preserve this fine set of speakers, love the clarity, depth and staging of them.

Best regards,

Willem.

 

[CJ]

What is the failure mode for film caps?

DC into a voice coil can cause a fire.

So if a lytic is self healing, that might be good.

No wait, that would be the amp's fault, never mind.
???

 

[abbey road d enfer]

B&W advises against replacing the bipolar electrolytics with film caps. They say they included the series resistance of the electrolytics into the value calculation for the other parts. So if you put in better caps you have to add small resistors in series.

Olaf

IMO, it's just to justify their choice of cheap components. The tolerance on ALL parameters of elcaps is so large that it's almost impossible to properly take them into account. And anyway the series resistance of inductors is much larger and thus much more significant in the design, that it makes the series resistance of caps almost irrelevant.

 

[playboss]

well someone just told me that a 400 uF foil is the size of a brick