life span/failure rate of filter capacitors?


(And I assume that the filter caps are the large electrolytic caps with the screw in terminals?)

The reason I am inquiring about this subject is that I stumbled on to an older thread started by someone who had a "filter cap explode" inside his 20 year old Cary V-12 monoblock.  (Which is basically what I have, only mine is a single stereo amp.)

Anyway, I do know the specs on those large caps with the screw in terminals which I am thinking are aka filter caps are 560uf 400v. 

Do these normally give any kind of warning before they let go?  It does occasionally blow the 3A SB AC power fuse on start up. 

TIA for any information/advice on this subject.

immatthewj

Before 2000 I would have said that generally 20 years for filter caps kept warm.

I think newer caps should do better, around 30, especially if high temp.

Caps may bulge or leak before complete failure, or get unusually hit compared to their peers.

Caps do sometimes go through poor quality issues which may cause premature faiure.

 

If in doubt have it recapped with the highest possible temperature ratings. More expensive, but higher longevity.

I seem to recall reading that thread or another elsewhere with Cary amps of that vintage. I ran Cary SLM100 monoblocks back in day, had the well known issues with Jensen coupling caps, also had issues with maintaining bias on power tubes and occasional fuse blowing, I'd replace those caps just to be safe, lots of inrush current with your amp, stresses the caps.

@immatthewj,

@jasonbourne52 Wrote:

Electrolytic cap lifespan is unpredictable! My Sumo Andromeda is still going strong while my BEL 1001 and GAS Son need new caps.

I agree! I bought my Luxman B-12 mono block amps new in 1977, the two main filter capacitors were 15,000uf 63 Volts and lasted 30+ years. And were up to spec when I sold them. If you are occasionally blowing a fuse, my advice would be to send the amp to Cary Audio and have them check it out. 😎

Mike

 

 

 

 

 

 

Something i do not agree is changing the temperature specs on vintage equipment.

If at 85 deg replace with same rating, and check to improve in other areas as voltage, tan δ, esr, etc ( depending on position)

Last, why should a higher temperature rating be more expensive? 

The truth is that after 20 years you maybe on the edge, and say maybe because i believe that good quality caps can last a very long time.

 

Nelson Pass stated that even after 20 years most of his products do not

need new caps. Maybe because he uses a lot of them?