Replace Electrolytics?

[Monjul]

Hi all.

I have both a Cary SLA 70A tube and a Kinergetics solid state crossover/sub woofer amp in which both are approaching the 20 year mark. The question is to whether or not I should begin to consider replacing the electros including the filter caps. If I do, I understand I can install storage caps as high as twice the uf value? Is this sound advice? Thanks for any responses.

[Glowbug]

Couldn't hurt

[Monjul]

Originally Posted by Glowbug

Couldn't hurt

LOL. True, but have you seen the price of good storage caps lately?

I was wondering if the experts here think that even if the caps still work, they're probably marginal in their performance. If that's the case, I'll spring for the cash.

[kruesi]

If it was my amp, personally- I would. I'd sleep better at night, knowing the filters were not about to let loose. But on the other hand, I have some 20-30 year old electronics with the original caps, and some of them continue to work well.

You could start measuring leakage currents, but it's easier and faster to just replace them with a good grade of capacitor- Nichicon, or if higher Voltage, Sprague Atom, or whatever your preferences might be. Everyone has their own favorite.

Oh- If they're 20-year-old "FP" twist-lock chassis mount cans, definitely replace them. No question about it in this case.

[Brit01]

I purchased an 18 year old SS amp a while back (Carver TFM-55).

I pulled out all of the electros and replaced them.
The 20,000 uF 200V ones were difficult to find though.

Ended up using some Panasonics.

Always worth doing every 20 years IMHO.

[Poindexter]

It is my opinion that Panasonic TSHA, TSHB, TSED caps are some of the most transparent power supply smoothers ever made by anybody at any price. I have tried some very expensive boutique caps, and these are the ones I use, for myself, and for my clients.

I think that a lot of folks think that, because they're economical and compact and generally low-suffering, they really can't be all that good. They are.

P

[Conrad Hoffman]

No doubt I'm in the minority, but I think replacing caps just because they're old is foolish. Caps should be replaced because of three things. They start to show excessive DC leakage, they lose capacitance or the dissipation factor rises. I have lots of caps in 40+ year old test equipment (yes, with tubes) that are performing (and measuring) fine. I've also had cheap electrolytics in solid state receivers and such that went bad after 5 years. Measure! Various people, myself included, have published easy circuits to let you do so. Or, buy an esr meter or a bridge. Anybody who's put off by measuring a cap certainly has no business deciding to change one.

CH

[Svein_B]

Originally Posted by Conrad Hoffman

No doubt I'm in the minority, but I think replacing caps just because they're old is foolish. . .
CH

At least there are two of us.

I see no reason to replace caps unless they are faulty.

Changing caps may alter the sonic signature of an amp. It could be to the better, but you might just as well find that you liked it better the way it was.

I have tried to measure a few 40 year old caps, and found them to be according to spec.

Svein

[Geek]

If the unit has been in frequent use, they are likely still good unless they are showing signs of leakage or drying out (low value).

Power supply caps might be an idea to replace for the lower ESR if in a critical unit, like phono, but a regular amp? Up to you...

Cheers!

[jean-paul]

Electrolytic caps of 20 years old that function according specs are rare. Especially when the rubber is crackled there is no doubt you should replace them ASAP. So replace them but make sure that you use quality stuff !

Replacing them for cheap standard electrolytic caps will result in premature failure ( probably even earlier than with the old caps ).

The old ones lived long partly because of their size. Also some brands produced fine quality caps. When they're good they're good but replacing them for fresh good quality caps never hurts. Leaving questionable caps in an amp just because you could change the sonical character is nonsense. If so you would accept errors because it is more pleasing to the ears ?!?!