Mains Hum - Are cheap caps worth it?

[HiFiWill]

Hi, thanks to the help of the forum I now have a working 405 clone. All I need to do now is up rate the power supply capacitors to 10000 uF 63v. I've seen cheap ones on Ebay but they look rather small. Is size important? Do you get what you pay for? I feel I know the answers already but - any advice gratefully received!

 

[SY]

Make sure that your hum is actually coming from the power supply ripple and that your grounding is impeccable. Given that, I would be VERY leery of buying cheap caps from China. I would stick to high reliability caps from first-tier suppliers, and sourced through reputable distributors (i.e., not some no-name counterfeit-flogger on EBay). Here in the US, a 10,000u 63-75V cap from Digikey runs $5 or so- why risk your amp to save a dollar or two?

 

[jaycee]

No it's not worth it. They will under perform and probably fail quickly. Go with the Panasonic TSHA range which you can buy from CPC or Farnell.

Having said that, I have bought BHC Aerovox and Cornell Dubilier capacitors from eBay without trouble, but they were not from Chinese sellers.

 

[digits]

You can also order from RS components in the UK, they offer free next day shipping.

 

[djk]

"Is size important?"

Yes, ripple current ratings are related to the size. Smaller caps have smaller ratings.

"Do you get what you pay for?"

Usually, yes.