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Multi-Way Conventional loudspeakers with crossovers

What to do with these crossovers?
What to do with these crossovers?
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Old 26th January 2011, 09:11 PM   #1
Phantom499 is offline Phantom499  United Kingdom
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Default What to do with these crossovers?

Hi, first off apologies for the dumb post.

I have a pair Bolivar Speaker Works Model -125 two way speakers and have just finished refoaming the surrounds on the 8Ēwoofers. They donít sound too bad but given that these speakers are 30 years old I was wondering whether the crossovers would also benefit from some work, if so what?

Click the image to open in full size.

Iím guessing the blue coloured capacitor in the centre of the picture would need replacing but what else? I know next to nothing about Diy audio and so Iím not sure what any of the other components are. Also is this the type of work that a Diy audio enthusiast would be able to do in exchange for some beer tokens or would I need to take them to a speaker specialist which I guess would be expensive?

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Old 26th January 2011, 09:45 PM   #2
gfiandy is offline gfiandy  United Kingdom
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So this is from arround 1980. If that is the case then the light blue electrolitic cap will need replacing as you guessed. The gold coloured component on end is probably a film capcitor if this is the case it is probably OK. If it is a wax paper cap then it probably needs replacing.

If its a foil capacitor it might say something like polyproplyeen or polycarbonate on the side which would identify it, (it also might not).

If it is a foil capacitor it is probably electrically leaky by now. If you have a multimeter you could identfy this by checking its resistance. After the meter has stabalised it should read > 1M ohm if it is much less than this then its probably a wax capacitor and could do with replacing.

The white component on its end and the grey component on its side look like inductors it is unlikley these need changing unless the speaker has been over drivern in which case they would look burnt.

The light grey / white comonents are resistors it is unlikely these need changing as they are very stable and don't look damaged.

So probably the only part that needs changing to return it to origonal performance in the light blue electrolitic cap.

If you want to try to upgrade it that is a whole different approach and unless these speakers are really good its probably not worth the cost and effort.

Changing the caps is something anyone who can use a soldering iron and is fairly careful can do.

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Old 26th January 2011, 10:26 PM   #3
Phantom499 is offline Phantom499  United Kingdom
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Join Date: Jul 2010
Hi Andrew

Thanks very much for the detailed reply.

Bolivar speaker were an offshoot of JBL and were available from around 75-80.

The item bottom left of the crossover pic is like a cardboard tube filled with wax so I assume that means it's a wax paper cap, fairly sure there's no writing on it so can't tell its value. Does changing old caps usualy give some sonic improvement or is it done just to increase longevity?

The speakers are pretty good with decent woofers but tweeters are paper cone which I beleive is a bit old school

pic taken before the woofer refoam
Click the image to open in full size.

Woofer rear view
Click the image to open in full size.

I think it would need someone far more experienced than I to look at them to decided if they would be worth a crossover upgrade so I think I'll just get the caps repalced for now.
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