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Replacing caps

 
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ajswinscoe
Intermediate Contributor 25+


Joined: 25 May 2007
Posts: 26
Location: wigan

PostPosted: Sun Nov 02, 2008 12:19 am    Post subject: Replacing caps Reply with quote

Im struggling to find a pair 5uf polly prop caps to replace an aged pair i have.
Im facing a choice of either 4.7uf or 5.6uf.
Im unsure what to do. Do i opt for the lower or the higher value ?
What effect will each option have to the sound ?
Will it be a noticable difference ?
The 5uf caps that are being replaced are from lf side of the crossover on my 104ab.
Thanks
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speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Sun Nov 02, 2008 10:32 am    Post subject: Reply with quote

Get the lower one and put a 0.33uF in parallel with it. Better still get hold of an LCR meter and measure what you get first. The 4.7uF caps you buy could be +/- 10%, 20% maybe??

Will you hear the difference? Depends how critically you listen. A rough rule of thumb:- 10% component value change will result in a 1dB change in some region of that XO band.
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ajswinscoe
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Joined: 25 May 2007
Posts: 26
Location: wigan

PostPosted: Sun Nov 09, 2008 4:24 pm    Post subject: Reply with quote

Ive already got some 5.6uf polyprop caps knocking around. I just wonderd if i used them, how it would effect the sound ?

I can get 4uf and 1uf from wilmslow audio. But how would i go about fitting them ?
Would i just solder the 1uf ontop of the 4uf so that the signal passes through them both at the same time ?
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sun Nov 09, 2008 6:35 pm    Post subject: Reply with quote

Yes indeed, connecting capacitors in parallel effectively increases plate area and thereby increases total capacitance.
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ajswinscoe
Intermediate Contributor 25+


Joined: 25 May 2007
Posts: 26
Location: wigan

PostPosted: Sun Nov 09, 2008 7:37 pm    Post subject: Reply with quote

Cheers andy. I shall do that then. A 4uf and 1uf cap it is then
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