Using audio caps on smps secondaries?

[Uranium-235]

I have three crapXon KMs. 25v, 2200u, 1.2Arms, no listed ESR. Classified as general. Closest I get is UCC KMEs, which are out of stock on mouser. The other ones are that are 1.2A are classified as audio caps. Are these suitable as replacements? Not even sure low ESR/high ripple are suitable replacements. Ive seen what happens on pc psus when people have tried replacing general purpose caps with polys

[stj]

Re: Using audio caps on smps secondaries?

never,
if they arent low esr they will heat up and burst!

[Stefan Payne]

Re: Using audio caps on smps secondaries?

Get shitty Low ESR ones.
Like Nippon KYA or Pana FC.

But Mouser has some good replacements like Panasonic M Series, maybe NHG series or Nichicon URS or UVP series.
Choose your poison...

[Uranium-235]

Re: Using audio caps on smps secondaries?

But the ones in there are not low esr and only fair ripple, they're not bloated, still I want to replace them though

[momaka]

Re: Using audio caps on smps secondaries?

But the ones in there are not low esr and only fair ripple, they're not bloated, still I want to replace them though

Doesn't matter. The manufacturer could have used those because they were cheap bastards. I've seen CapXon KM used quite often in LCD monitor PSUs, and those are pretty much always flyback topology (in fact, I haven't seen one that wasn't). If anything, flyback topology actually works very well with caps capable of high ripple current and low to very low ESR. So using general purpose caps on such a topology is usually done just to save money for the manufacturer.

Now if it's just a regular non-flyback SMPS, you should probably go with entry-level low ESR, like Panasonic FC, Nichicon PS/PM/PW/PJ, Rubycon YXJ, or Chemicon KYA.

As to the question in the title: yes, you could probably get away with using audio-grade caps on SMPS, but it's not recommended. Audio-grade caps usually have higher ripple current capability at low frequencies (typically compared at 120 Hz or 1 KHz) compared to both general purpose and low-ESR caps. At higher frequencies in the 10's to 100's of KHz range, low-ESR caps have higher ripple current. So essentially, low-ESR caps are more suitable for high frequency circuits.