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Beginners help/advice required

SamanthaJ

SamanthaJ

Member
Hi all. I have some 40 year old Sony speakers that need their capacitors replacing - as I don't recall them ever having been.

I'm quite technically challenged but opened the speakers up and found a blue capacitor in there 2.2uf 50v. It was a blue one with wires coming out of each end. The speakers are only 2 way and don't have a cross over in them. I was looking to replace this blue capacitor but can't find an exact replacement (new ones being 2.2uf 100v) and also, having had a quick look on this forum, it seems that a special hifi type is needed anyway.

So, can any of you help - please? I have looked at the pinned threads with links but got totally confused. Does anyone know where I can find one of the above capacitors and have a link of a good, UK supplier.

Thanks :)
 
Have a look in the d.i.y. section of PinkFishMedia. The first thread there is "pinned", and gives information on where to obtain components such as capacitors.
 
Hi Samantha

The increased voltage of the newer capacitor is likely a good thing. The main thing is matching that 2.2uf rating.

There's lots of different types and you can spend a lot... Quite unnecessarily, a lot of the time. See what you can glean from the DIY room, but you can always default to a semi decent 2.2uf poly capacitor from Solen, or similar.
 
Get a pair of Russian K73-16 100V from eBay. Ask the seller to match them and get them as close to their stated value as possible - very important.

Solen 5% matched from Falcon acoustics would be your other option

The cap is the crossover

Good luck
 
Dan K said:
Get a pair of Russian K73-16 100V from eBay. Ask the seller to match them and get them as close to their stated value as possible - very important.

Solen 5% matched from Falcon acoustics would be your other option

The cap is the crossover

Good luck
Click to expand...

when buying on eBay I’m pleased when the package that arrives doesn’t just contain gravel.

clearly I need to lift my expectations
 
It is important you get a bipolar capacitor. The polypropylene caps linked to above should be fine. Electrolytic capacitors are mostly unipolar, but you can get bipolar types. There is no need to get an electrolytic at this small capacitance. I mention this just in case you look for different types. There is also no need to get any allegedly hi-fi grade caps.

Why do you think the capacitors need changing? The only ‘change on sight’ caps are some very old ones like Hunts ‘mould seals’ which have often fallen to pieces. Electrolytic types can dry out, but this is probably not that type anyway. Some types are very stable and will not need changing. You should test the cap to see if it has drifted in value or has high leakage. However, if you don’t have a suitable test meter, I acknowledge it may be more cost effective to simply change them if you have a soldering iron to hand.

EDIT: I should correct my terminology and say that by bipolar I mean unpolarised (or non-polarised) and by unipolar I mean polarised. Non-polarised caps can be connected either way around and this is needed for a speaker cross-over where the current flows both ways
 
Thanks Mark. I'm hoping it's a cheap fix, though equally it could just be that the speakers are blown. A couple quid on a couple replacement capacitors appeals more than new(er) speakers.
 
SamanthaJ said:
I'm hoping it's a cheap fix, though equally it could just be that the speakers are blown.
Click to expand...

What are the symptoms? Blown drivers will typically 'rub', which makes a papery rasping sound. If they are badly blown you'll get this at all times but sometimes they can play fine at low volume and only rub as the volume goes up.
 
Mr Pig said:
What are the symptoms?
Click to expand...

Indeed, this is the key question. If the only component in the cross-over is a capacitor, then it should be in series with the tweeter acting as a high-pass filter to block the low frequencies from the tweeter. Even if the cap is open circuit, you should still get sound from the bass / mid-range unit. The cap will only affect the sound from the tweeter.
 
Mr Pig said:
What are the symptoms? Blown drivers will typically 'rub', which makes a papery rasping sound. If they are badly blown you'll get this at all times but sometimes they can play fine at low volume and only rub as the volume goes up.
Click to expand...
That, and distortion via the midrange/tweeter on midrange sounds. It's like the sound is bleeding into the wrong speaker. Just sounds unbalanced, yet if I plug other speakers into the amp they sound very nice.
 
SamanthaJ said:
That, and distortion via the midrange/tweeter on midrange sounds. It's like the sound is bleeding into the wrong speaker. Just sounds unbalanced, yet if I plug other speakers into the amp they sound very nice.
Click to expand...

Well, if the tweeter is still giving output, then it shows the voice coil is not burnt out. The problem could be the cap that is allowing too much low frequency into the tweeter. Be careful - this could damage the tweeter. So, worth changing the caps. However, it is still possible that it could be damage to the tweeters (or the tweeters have become damaged).
 
Just a point, a conventional two-way speaker has a bass / mid-range unit and a tweeter for the high frequencies only. I'm not sure what you mean by 'midrange / tweeter'.
 
Mark_R said:
Well, if the tweeter is still giving output, then it shows the voice coil is not burnt out. The problem could be the cap that is allowing too much low frequency into the tweeter. Be careful - this could damage the tweeter. So, worth changing the caps. However, it is still possible that it could be damage to the tweeters (or the tweeters have become damaged).
Click to expand...
My fears. Apparently they had been sat unused for decades, though had previously been very loved judging by their condition. Once the issues presented themselves I have not used them. A quick google suggested capacitors and the rest is history.
 
Mark_R said:
Just a point, a conventional two-way speaker has a bass / mid-range unit and a tweeter for the high frequencies only. I'm not sure what you mean by 'midrange / tweeter'.
Click to expand...
The top one of the two. I didn't describe it well. It is just a two way speaker. The smaller, midrange? seems to bleed sound and/or distort. It might be blown but I was hoping the capacitor as a cheap fix.
 
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