Hypex NCore bad capacitor and no convenient replacements

[Taylorjay]

I've had my 8-channel Hypex amplifier (built by Nord) for about 8 years averaging light use. Up until now, I have had zero problems with it. Then I tested our house's emergency backup generator and, immediately after switching the power back to grid power, the subwoofer channel on both speakers started producing mid-low crackly distortion. It faded to nothing in about 30 seconds, but it comes back briefly when I walk past, and it's persistent when I'm playing music.

Grok thought the dirty power supply stressed and ruined one of the capacitors, so I opened up the amp and found on the NC252MP module powering my subwoofers does in fact have a swollen capacitor (bottom left on the picture).

According to the information printed on it, it's rated at 470 uF, 63 V, and it measures about 6.6 mm in diameter. Looking online for a replacement capacitor (even from the manufacturer printed on it, Su'scon), there are no equivalent options even close to that small! I found an alternative on DigiKey that I can use to replace the four of them in that cluster, but it's 13 mm in diameter. We'll be able to make the larger ones work by having them stick up pretty far, which the amp casing has room for.

I have minimal electrical engineering knowledge, but a friend helping me is pretty experienced and thought this was very strange.

Anyone have any insights on this? Maybe the original capacitors aren't rated up to 105 degrees and use hybrid polymers? Or Su'scon is producing some custom capacitors for Hypex?

I'll update this after we make the repair and let you know if it fixes the distortion, which will hopefully help any others who have this issue in the future!

 

[Matias]

Have you tried contacting Hypex customer service for helping with parts selection or instructions, even after warranty? I suppose they could have helped.

Also was the amp turned on while switching the generator on and off?

 

[Taylorjay]

Have you tried contacting Hypex customer service for helping with parts selection or instructions, even after warranty? I suppose they could have helped.

Also was the amp turned on while switching the generator on and off?

That's a fairly obvious idea that somehow I didn't think of! I just reached out to them. I'll update if they respond with anything useful. Thank you.

 

[Chanur]

I'm assuming you contacted Nord or Su'scon directly?

 

[rossv]

Check the diameter again, I am quite sure the diameter is 13mm not 6.6mm.

 

[ferongr]

Must be our lucky day, both of us.

Impressions and internal photos of the Audiophonics MPA-S250NC

By the way looking at specs the input sensitivity is 1.6 mv ,my other amps are at 2 mv. You would probably say and you will be right that the difference is marginal but just for informational purposes is there an adjustable gain in these amps ? I think some other makers offered that might it...

www.audiosciencereview.com

These 8 caps are part of the output filter power rail (thanks @boXem) of the amplifier. Dimensions are 12,5mm X 20mm. Original Sus'Con el cheapo caps are of the SK series, with 2000 hours rated life at rated temperature. I'm going to replace mine with Nichicon UPW1J471MHD that I can find from a reliable supplier. Those have the same exact dimensions, 7000 hours rated life and a low ESR and high ripple current. You can go to 30mm cap height (depending on what caps you can find) without exceeding the amplifier's footprint, so you won't have issues with case fitment if it has a short height.

 

[AnalogSteph]

Dimensions are 12,5mm X 20mm.

Now that sounds a lot more realistic. It ought to have been really long and slender otherwise. It would not be uncommon for a 470µ/63V to be 16x20 (with the 330µ/63 V model being 12.5x20 instead), so I would suspect that the voltage rating may be anything but generous. Performance may vary between manufacturers even at the same size, but if a part is unusually small and from a third-rate manufacturer that's reason to be suspicious.

 

[Taylorjay]

Have you tried contacting Hypex customer service for helping with parts selection or instructions, even after warranty? I suppose they could have helped.

Also was the amp turned on while switching the generator on and off?

Hypex responded quickly and were very helpful. Apparently my calipers were measuring wrong because they said those capacitors are actually 12.5 mm.

Yes, I made the mistake of leaving the surge protector on when I switched the power over.

 

[Matias]

Happens to the best of us. Welcome to ASR by the way.

 

[Taylorjay]

Now that sounds a lot more realistic. It ought to have been really long and slender otherwise. It would not be uncommon for a 470µ/63V to be 16x20 (with the 330µ/63 V model being 12.5x20 instead), so I would suspect that the voltage rating may be anything but generous. Performance may vary between manufacturers even at the same size, but if a part is unusually small and from a third-rate manufacturer that's reason to be suspicious.

Agreed. Calipers were apparently not working right. Hypex was helpful as well. Kudos to their customer service.