Anybody ID these caps for me?

Discussion in 'Pickups & Electronics [BG]' started by Silver Blues, Nov 5, 2012.

  1. Hey guys and gals,

    I was just rifling (for the what, third time) through my available stash of defunct electronics in search of capacitors suitable for use as tone caps. I have a pretty big stash going now, which is OK by me, variety is good. :p

    But I digress. My real question is about three pairs of very special caps I found during my excursion. I have and am missing information about all three of them, and I was wondering if any TB electronics gurus could help me out.

    1 - I know that these are 0.047uF, however I don't know brand or material. They look like PIOs to me, but I don't really know.

    2 - I don't know anything at all about these, no value, no material, no brand, no polarity... :help: I'm hoping someone else has seen them.

    Third one in a new post...

  2. 3 - I know these are 0.03uF, but no material or brand. They look sturdy, have to say.

    So yeah, can anybody help me out plzzz???


  3. First one is paper in oil. Second looks like a Ceramic capacitor, though they tend to be flatter, whereas yours are fairly fat and round. Third looks like a Polymer (OsCon?) or Aluminum Electrolytic.
  4. I thought maybe they were polyester film like the myriad of green "chiclet" caps I have; you're right, all my ceramics are disc caps which these don't seem to be. Do you by any chance know what the value might be on these? Stupid no markings. :crying:

    Yeah, it could be either... if it is an electrolytic does that make it immediately unfit for instrument use like all the other electrolytic ones?


  5. megafiddle


    May 25, 2011
    The color dots on #2 look like red and violet, so I would guess a "27" for the digit part
    of the value.

    Can you read the 3rd color?

    Caps that small are non electrolytic and have no polarity.
    The band at one end of cap #1 indicates outside foil. That terminal was important in RF circuits,
    where it could be connected to a grounded point in the circuit and the outside foil would shield the rest of the cap.
  6. megafiddle


    May 25, 2011
    I should have said that caps that small in value are non electrolytic.

    If #3 is an electrolytic, it's value will be way too high for use as a tone cap (if that's what you are using them for).
  7. Don't use Aluminum Electrolytics and Tantalums and such for tone controls. Any other non-polarized cap works fine, however. Makes no difference in that particular application.
  8. Yup, two reds, a violet and the third is gold.

    0.03uF is too high for a tone cap? :confused: I don't think so.

    Okay, yeah that's what I thought.

  9. Red is 2, purple is 7, gold is *10[SUP]-1[/SUP].
  10. megafiddle


    May 25, 2011
    No, .03 uF is way too low for an electrolytic.

    If it is .03uF, it is not an electrolytic.
    If it is an electrolytic, it is not .03 uF, but would be much higher.

    Hope that makes sense.
  11. Thanks. See, that's too small. Oh well.

  12. It does, don't worry :D

    It has to be 0.03uF, because it's code is 303. So it's not electrolytic then... good.

  13. megafiddle


    May 25, 2011
    Reading from one side to another, is it red, violet, red, gold?
    That might possibly be 2700 pF (.0027 uF) 5 percent tolerance.
  14. Exactly right. Either way it's still too small... :meh:

  15. Okay well thanks guys, you were all a great help, I think I've got all the info I needed. Amazing what you find on old circuit boards.


    I didn't know my camera did such great macros. Those are nice clear pictures. :bassist:
  16. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    #2 looks like tantalum caps. I doubt there's any oil in the first ones, they just look like mylar caps.

    Pick caps based on the value of the cap. The type of cap wont matter for a tone control and they will all sound the same.
  17. IK, I was just curious. If it did matter, I would spend a week trying out all my caps in each new bass :p

  18. Question answered, taking down the attachments. Thanks all.

  19. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    How to measure a cap without a cap meter.

    Seems pretty straightforward to me. A lot of caps are in the uF range so odds are it will work.
  20. That's odd, kinda cool. I don't run into situations like that often though, 9/10 times I know the value but not the material type, polarity etc.