After reading about fake electrolytic capacitors on the ampgarage.com forum I noticed that the caps in question are the same “ELON” brand that I purchased from Weber some time ago. I used most of them in my 5 watt SLO amp. Since the day I built it there were some reliability problems that I never managed to fix completely. After playing for 10-20 minutes sound would suddenly change or it would start to motorboat when there’s input signal.
What gives them away is the way leads are terminated. On a regular cap they are soldered to the terminal on the can, but on these there’s a hole that leads to the inner cap(s). Photo below shows an ELON cap compared a F+T cap.
I opened one of the leftovers to check and sure enough it’s fake. Inside 20uF 500V ELON axial cap I found one marked as 100uF 160V G-LUXON. When I opened that one I found another one marked 22uF 400V KMG which seems to be the original cap. The worst thing about this is not re-branding or labeling a 400V cap as a 500V cap. The inner cap is most likely pulled from an old PCB because it has very short leads. Longer leads were soldered to them and threaded though holes on the largest can. So you’re effectively buying a used cap that came from who knows where and was pimped up by poor Chinese kids to look like a new cap.
It’s not my intention to discredit Weber for selling these caps. It’s apparent that they were scammed just as well. These caps may or may not work reliably, but when making an amp I always want to do the best I can and using caps that came from a trashed fridge or something doesn’t seem like a good idea. After these I have switched to European made caps like JJ and F+T. Few bucks I saved on getting these ELONs instead of some better caps don’t seem to be worth the frustration.