Film capacitors for bypass

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Hi

I got my hands on these film caps. I'm not sure what brand they are. Are they good for bypass/decoupling? I am thinking of replacing the ceramics in my cd player with these.
What, in your opinion, are the best caps for bypass/decoupling?
 

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Sprague and Siemens made stacked film parts in the 80s. The Siemens parts had a blue epoxy coat on the ends to help keep the leads from falling off when soldered, a common affliction with the stacked film parts of those days, as well as some of the ceramic multilayer caps, which were just chip caps with leads tacked on and dipped in epoxy (still are, but they're generally better made these days). At any rate, the parts shown might be old stuff from Sprague. I just picked up some old 220nF stacked film parts (probably Sprague) this weekend... Epcos still makes some stacked film capacitors - I just recently bought a bunch for a project at work. Panasonic may also still make them, though they coat theirs with their usual brick-red epoxy - check Digi-Key.

Edit - Having looked at the parts in question again, I would guess that they're old Sprague parts, as the leads aren't too well anchored in the end metallization - probably the reason for the tendency to fall off when soldered. Be careful. Otherwise, good parts with low ESR and ESL (though they are polyester - Siemens made some polycarbonate stacked film caps back then, but I believe all the currently manufactured stacked films are polyester).
 
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stefanom said:
What, in your opinion, are the best caps for bypass/decoupling?
That depends on what you are bypassing and why. For bypassing digital spikes you probably can't beat the appropriate ceramic cap - which your unit probably already has. Note that in some cases high ESR is a requirement for this application.

As others have said, what you have there appear to be bog standard polyester caps. Will be low inductance and low ESR, but perhaps a bit nonlinear like polyester usually is. Fine for decoupling where these characteristics are appropriate.
 
I should have said the inductance is a problem for bypass use.

I found some interesting non-polarized audio caps for DC blocking. They are not the old style back to back polarized caps, but actually designed as non-polar. If you are upgrading an existing design they may help.

I will have to wait until I get home to get the line name since I can't seem find them in Digi-Key right now (I am at work).
 
there are myriad of good sounding coupling caps, how good they sounds depends on your preference and the whole system of course. My trick is using what I have in my drawer and try them one by one, be it paper in oil, mkp, mks, etc. I visited junk shop now and then and grab used parts just to try, if lucky I can get good sounding caps
 
These stacked foil caps are good for lowish inductance, not the opposite.
These stacked foil caps are good for lowish ESR, not the opposite.

That makes them bad for decoupling where there are other capacitors nearby.

These stacked foil caps have very low leakage. That makes them good for DC blocking, not the opposite.
 
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