[HAM] old capacitors

[David Anderson]

Benjamin,

Maybe I missed something, but did ANYONE on here suggest using new  
old stock capacitors, i.e., ones that have been sitting around for  
30-40 years? If so, I missed it. The question was whether to use new  
production cans or individual capacitors mounted some other way.

To Keith Clark: looking at some Sprague Atoms I have, for example, it  
seems to me that four of them combined are physically larger than one  
of the old can capacitors with the same values. I'm aware that there  
are trade-offs using miniaturized capacitors, so I try to use larger  
units when possible. For that matter, the new production CE  
Distribution capacitors are often smaller (shorter) for the same  
values than the old ones. You do have a point about size and  
capacitor life, but I think reducing it to multi-cans vs. individual  
units doesn't answer all the questions.

And as I think everyone agrees, the big enemy of electrolytic  
capacitors is heat. I've seen many old tube amps where the can  
capacitors were mounted too close to a hot rectifier tube; in almost  
every case, the capacitor is bad. In this case, putting capacitors  
somewhere else, regardless of how you do it, will greatly increase  
capacitor life. This is not a huge issue in the AO-28, although you  
certainly don't want to mount capacitors close to any of the  
wirewound power dropping resistors under the chassis.

David

On Feb 18, 2008, at 2:20 PM, benjamin wrote:

>
> Hope I have helped a bit in contributing to this forum with some  
> insight
> into Electrolyts caps , so please Use NEW and fresh produced  
> quality ones ,
> not Old 'gold'   that is  dried out and corroded inside; If you  
> want them to
> look like Oldies , then open up the old can and put the new one  
> inside ,
> fill it up with some kind of polyester and there you have your ''oldie
> looking' good cap !
>