samwha capacitors 10uf 200v/250v

[Perry Babin]

The attached capacitors are used in the output filters of class D amplifiers and hold up well but when they fail, replacements are difficult to find. I've tried the various options on eBay and crossover caps and none survived. Mouser, Digi-key... don't stock many bi-polar electrolytic caps. The only thing that I found survived (never a failure) was the Mouser E2106 (part number 667-ECQ-E2106JF) and the same from Digi-key. They look different but survive. Does anyone know a readily available drop-in replacement electrolytic? The dimensions are approximately 16mm x 25mm.

[stj]

it's BI-POLAR, you can use a polyester film cap if it will fit.

[Perry Babin]

That's what I've been using. They work perfectly but there isn't always space for them.

[momaka]

Those caps can be subjected to a lot of ripple current, so it's no surprise they fail. Going with film caps is indeed the only long-term reliable option.

There used to be very high ripple current bipolar electrolytic caps made for CRT monitors... but with those gone the way of the Dodo bird, the need for these caps has also diminished and so pretty much none are in production, AFAIK.

I'm not sure if this will save you any space, though it may at least provide equally reliable results: using two POLAR electrolytic caps back to back in series with reverse/protection diodes across (a.k.a. poor man's bipolar electrolytic cap.) The diodes will allow for higher currents without damaging the caps, since each cap can only get reverse voltage up to the diode's forward voltage (V_f) - typically 0.7V, depending on the type of diodes used. With Schottky diodes, that can be reduced down to 0.2-0.5V.

[Perry Babin]

The back-back electrolytics are commonly used but they don't use the diode. The reverse voltage applied to one cap on each half-cycle doesn't seem to be a problem (doesn't cause failures). I don't know if it's common for other circuits that use caps in this way but they use two capacitors with 2x the rail voltage. For ±80v rails, they use two 200v caps in series.