[AtomBoy]

What parts can stand to get a little old and dusty? Is it nuts to try to use a capacitor that might be 20 years old?

I'm lucky enough to have some great surplus stores nearby. Lots of their stock is stuff that Uncle Sam probably paid a fortune for and then forgot to put in a rocket or fighter jet and might sound really good in a headphone amp. We're using tubes that have sat on the shelf for a while. What else doesn't get all limp and smelly when left in the crisper too long?

Are there any rules of thumb for finding rocket-grade bits that they just don't make that way anymore?

 

[Fresno Bob]

AtomBoy I have caps that are 20 years+ old and they work, and hold capatance fine. i have res that are as old as the caps, and they work. i have ic's over 20 years old too. if you can find a use them they will work esp the mil spec stuf they. enjoy.

 

[CPL593H]

In general the cost of components is cheap compared to the time and effort you put into an amp why use old stuff unless you want a 'vintage sound' as in restoration of old amps where you might want some old carbon resistors or NOS caps.

 

[nikongod]

Quote:

Originally Posted by CPL593H In general the cost of components is cheap compared to the time and effort you put into an amp why use old stuff unless you want a 'vintage sound' as in restoration of old amps where you might want some old carbon resistors or NOS caps.

price. a 2h choke coil for $5 is hard to beat....
quality (maybee) see below.
and "wow" factor. sort of falls under the general vintage thing.

there are some older caps that have VERY large advantages over newer ones. specfically ones made with some filthy dirty harmful chemicals, but they do amazing things in electronics. some old stuff, i do agree is just cool because its old, but some of it does unquestionably (iognoring envyromental/health concerns) works better than the newer stuff.

is asbestos a better insulator/flame retardant than fiberglass wool? if you ignore the fact that it WILL cause all sorts of respratory issues, yes.

 

[amb]

Electrolytic capacitors gradually go bad if unused for many years, and may heat up, bulge, leak or even explode if full voltage is suddenly applied to them. Some may be "reformed" back to spec by applying a low voltage with current limiting, and then slowly increasing the voltage over several hours or days, but there is no guarantee that this would revive all of them.

Do a google search on "electrolytic capacitor reforming" for more details.

 

[AtomBoy]

Quote:

Originally Posted by CPL593H In general the cost of components is cheap compared to the time and effort you put into an amp why use old stuff unless you want a 'vintage sound' as in restoration of old amps where you might want some old carbon resistors or NOS caps.

Well, 'cheap' is always relative to your budget. Also, I'm less concerned with the absolute last 5% of performance than I am with learning how things work so sometimes I'll want lots of different values or types of a part.

I just want to avoid the parts that might have changed values over the years, or might explode (when I don't want them to). It would also be neat to use stuff that was bought for a Cray supercomputer or something- just aesthetics (and maybe that last 5%!).

 

[rickcr42]

Quote:

What parts can stand to get a little old and dusty? Is it nuts to try to use a capacitor that might be 20 years old?

there is an article to the "reforming old capacitors" article in the links section (I think,if not let me know and i will add it)

 

[CPL593H]

You're right about cheap being relative sorry if that came off as crass.

From my limited experience with old tube amps the only components that I've seen problems with are electrolytic capacitors and selenium rectifiers. In old radios I've seen leaky capacitors that may not be electrolytic like some sort of oil dieletric things. I've read that some old solid state devices had limited life due to corrosion, delamination and other age/temperature related problems. If you avoid electrolytic caps as noted by others here you should be safe.