Old crossover capacitors - what type are they?

[Beobloke]

Silly question and one which I would have thought would been easy to answer, but no-one seems sure!

The old 'Elcap' capacitors that one finds in old loudspeaker crossovers that have a black body and red ends (see attached picture) - what type of capacitor are they?

The name and a couple of websites suggest they are non-polarised axial electrolytics but I always understood they were some sort of film type.

Can anyone confirm either way?

[Cobaltblue]

Look like non polarised electrolytics to me .

Cheers

Mike T

[GrimJosef]

If you've got access to an ESR meter that should tell you. Most films have negligible ESR. Likewise if there are microamps of leakage current then either it's an electrolytic or the film has failed.

Cheers,

GJ

[G6Tanuki]

33 Microfarads in a case that small implies electrolytic technology rather than any of the fixed-dielectrics.

Non-polarised electrolytics would be my guess too; in a crossover network you shouldn't be having to deal with any DC component so it would be an easy job for an etched-aluminium-oxide electrolytic.

[Valvepower]

Hi,

I join the electrolytic capacitor camp, as I remember using those - what has the be something 40 years ago - in crossovers and they were a non-polarized electrolytic.

Terry

[Hartley118]

Philips call their electrolytic capacitors 'elcaps'.

These examples certainly look like non-polarised electrolytics.

Martin

[stevehertz]

Surely the giveaway is that both ends are coloured red and that similarly both ends are marked +ve - in other words an electrolytic that can be connected either way, a non-polarised electrolytic.

[Trevor]

Kef loudspeakers were full of these

[dazzlevision]

These look very much like "Callins" electrolytic capacitors in appearance and labelling, which weren't very long lived in TVs (possibly due to the heat). I would treat them with suspicion and replace.

[paulsherwin]

They certainly look like non polarised electrolytics to me. Plastic film caps of that capacitance from that era would be huge - they'd still be pretty big made today.

[dazzlevision]

Originally Posted by dazzlevision

These look very much like "Callins" electrolytic capacitors in appearance and labelling, which weren't very long lived in TVs (possibly due to the heat). I would treat them with suspicion and replace.

See post #15 in this thread: https://www.vintage-radio.net/forum/...ad.php?t=98964

[fetteler]

They are absolutely 100% definitely non polarised electrolytics. They were used in all sorts of speakers in the 1970's. Wilmslow Audio - a big supplier of homebrew speaker bits - used to sell them. Replace on sight as they will be completely done in.

Steve.

[Lucien Nunes]

I would also be inclined to replace them as a matter of course, however I have found a fair percentage still usable. I recapped a couple of sets of Kefs last year and on one pair of crossovers, all but one cap in each (the same value) were fine for capacitance, ESR, leakage and reasonable for loss.

[Diabolical Artificer]

These same type are in my Mission 720 speakers and checked out ok but hifi collective do replacements. They're electrolytics as others have mentioned, a film type would be much bigger especially vintage film types. I have some 10u film caps from the 70's that are huge and wouldn't fit on a small PCB.

Andy.

[Beobloke]

Thanks everyone - electrolytics they are, then!

Originally Posted by fetteler

Replace on sight as they will be completely done in.

Steve.

Oh, don't worry - I always do. The speakers I've just refurbished had, amongst others, 2 x 40uF in parallel at one point in the crossover - the one set I measured came out at 112uF...

[Glowing Bits!]

Them capacitors are use don Wharfedale speakers, they are good while working but will eventually start acting strange, the usual sound resembles the speaker being in the bath.