AR4x Crossover

[Tyler]

I posted an image of the crossover from my ar4x, Is that block under the coil of wire a factory capacitor?  If so It's a lot different from my other speaker which has a silver can type which I recently replaced.  My other question is, should I replace it?   

Ty

[Tunedguy57]

Hi, those "Industrial cond.corp" capacitors were mounted by factory....were really fine and well sounding (paper in oil) but after 40 (or more) years can have gone out of tolerance.

In particular it's not so rare their value has become more than 50%. It's a dangerous situation for tweeter!

In order to fix your 4x's I should change both with a parallel of a 15uF and a 4.7uF plastic film. I should avoid a 22uF. Better not to stress your valuable tweeters.

Best results could be obtained with paper in oil, but they are somewhat expensive nowadays.

PS: it s not so rare finding in old AR boxes different capacitors. In particular can be found Industrial paper in oil and NP electrolytics (often by Sprague).

They mounted indifferently both so your pair may have both inside.

tunedguy57

[ra.ra]

The pair of speaker crossovers shown here (with #5 coils, however) had the same situation regarding mis-matched capacitors, and even though the can-type caps often still measure reasonably well, it is a good idea to replace both 20 uF caps at the same time. You can always parallel multiple smaller caps to achieve this value, or simply replace with a single good quality cap of the same value. And if you want to ensure the best HF performance from the tweeters in your restored speakers, while you are inside, you should also inspect, and then decide whether to clean or replace the pot controls. 

[Taaron]

When replacing the caps, what happens with polarity of the new cap. The old paper in oil do not specify polarity.

Thanks

[JKent]

Caps must be non-polar. Either film or non polar electrolytiic

[JKent]

These will work fine https://www.madisoundspeakerstore.com/carli-capacitors/carli-mylar-20-mfd/