Old coupling caps

[dscottguitars]

Hi, what's everyone's opinion about using old caps like these?

[DummyLoad]

used: circular file. NOS: test first.


--pete

[sluckey]

All of those caps would go in the trash can.

[jjasilli]

I'm a fan of of old plastic caps: Sprague, Pyramid, Sangamo, to name a few. I think they tend to retain their uF value, but you may as well just assume they leak DC.  So I do use them for guitar tone caps.  They could also be used in a tonestack assuming that a coupling cap is already blocking DC to the tonestack. 


Why use them?  It depends if you believe that different caps impart different one.

[dscottguitars]

Thanks for the responses. I am selling them on ebay.

[terminalgs]

those bumble caps (in your pic, far right) are terrible for leaking DC.  i recently tested about 20 that I had clipped out of parts tape machines.   the test scenario was as a coupling cap with 100v on one side, and 470K resistor to ground on the other. maybe 2 or 3 didn't leak any DC,  the others leaked between 10V and 50V.


I have a 50's AM/FM Zenith radio that had one of those  serving death-cap duty.  I listened to the radio daily for 5-6 years.  One day came a loud pop! then smoke...  see below, the bumble bee exploded.







they are really just absolute junk if DC voltage will be on either side of them.

[Platefire]

I would never use used caps. I have used NOS caps when to keep from making an order for one or two to finish a project. Too much work to risk a premature failure on a used cap. Platefire