25v 40 micro farad capacitors

[conor4]

hi , i am looking for replacement capacitors for my beovox 3800 2 ohm speakers.
they are around 30 years old. i read in this*thread that replacing the caps might improve mid and upper range performance.



does anybody know a decent uk supplier (or overseas) that might sell this kind of thing? I had a look around a few sites but i couldnt find any that match the exact specs


http://forum.beocentral.com/viewtopic.php?t=60

Thank you very much!

Conor

 

[AMV8]

Hi
Try Wimslow audio ( who specialise in speakers ) or Farnell ( who supply electronic parts )
I am not sure how familiar you are with electronics but you need a capacitor that is 25 volts or greater and 40 mf plus or minus 10/15 percent.
I would recommend changing all the capacitors if 10 years old.
Don

 

[conor4]

thanks !

I didnt know that you could use higher voltages. hopefully my speakers will sound much better after.

Thank you.

 

[AndrewT]

40uF is an unusual value.
It might be worth trying 22uF+18uF to give the total value.

 

[richie00boy]

Try motor run capacitors, they come in 40uF. I got some for an active speaker project (basic tweeter protection), they are absolutely huge though and I think were about £8 each from CPC.

 

[conor4]

i had a look at the wilmslow audio and the only 40 micro farad ones they had were 630 v

if i am only after 25 volt ones will these still work in there place? i dont want to compromise if i can.

If i were to add up the capacitance from two caps is that going to compromise on sound in any way?

thanks people , i really apreciate it. my speakers are good as it is but the upper frequencies could be better, hopefully this will help them out.

while i'm at it does anybody know of any decent amps capable of running 2 ohm speakers?

 

[AndrewT]

any decent amps capable of running 2 ohm speakers?

Krell and Krell Klones.
see the KSA50 thread. PCBs still available.

 

[richie00boy]

It's perfectly fine to have more voltage capacity than you need in a cap, what you don't want is less.

 

[h_a]

I'm not sure everybody here is aware that these parts are probably polypropylene caps (MKP) and these do not need to be exchanged after 10 years. That's about the rule for electrolytic caps.

Well, but that's DIY, so go for it if you want.

Far higher voltage ratings are no problem, need just much larger space.

All the best, Hannes

 

[AndrewT]

i had a look inside and the one of the existing caps is a 40uF 25V capacitor.

I will guarantee that B&O have not used an MKP 40uF 25V in this speaker.

 

[h_a]

Ah ok!

So it's a bipolar elco, I guess in the low-pass for the woofer.

In that case a polypropylene probably will not improve sound very much, but it won't hurt in any case

Have fun, Hannes

 

[conor4]

i read a thread on the beocentral website saying that because these speakers are probably 30 years old the caps would probably be in poor condition. supposedly this manifests as poor high frequency reproduction. the caps that it came with were never regarded as being very good.

Thank you for all your help.

 

[richie00boy]

If it's a 20+ year old electrolytic, regardless of where it is it would be an advantage to change it. For reliability if nothing else.