In a bind and the clock is ticking (cap help)

Discussion in 'The Projects Forum' started by joekr11, Jul 3, 2010.

  1. joekr11

    Thread Starter New Member

    Jul 3, 2010
    4
    0
    Hi guys,
    I donate most of my free time repairing music instruments for a rock n roll high school for kids in AZ. I recently took on a bass amp repair that is on a tight deadline and I'm kind of stuck. I have a cap that burned off on the tube side of the preamp. Easy enough repair, but turns out the cap has a number that I haven't seen before and I can't find anything on line about it. The number is 474J 100N. The 474J is no problem I knnow what that is. Its the 100N that has me confused. Any insight would really---REALLY be appreciated. I gotta have this thing on stage on the Forth! Thanks!
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Do you have a make and model? Some of the members here are expert in looking up manuals.
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
  4. joekr11

    Thread Starter New Member

    Jul 3, 2010
    4
    0
    Wow! Thanks for the fast replys! I'm taking a picture right now. in the mean time the Make/Model is Hartke 2115 combo (2000 series head and 1 15" speaker in same cabinet.) I've emailed and called Samson/Hartke and they won't give me the time of day.
     
  5. joekr11

    Thread Starter New Member

    Jul 3, 2010
    4
    0
    ok sorry about the poor pic quality, my camera is ancient.
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
  7. joekr11

    Thread Starter New Member

    Jul 3, 2010
    4
    0
    i can't thank you enough for the help!!!!
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Actually, that looks rather like some old silver mica caps that I have. However, the ceramic should do just fine; this isn't an RF application.
     
  9. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    Afther having a second look at it, SgtWookie is right.
    It is a silver mica capacitor.
    For an audio application the ceramic I showed you will be OK.

    Bertus
     
  10. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    I would say it is NOT a silvered mica capacitor but a Mylar one.

    A silvered mica capacitor of this capacitance will be very large in size. Also the 100V rating does not seen common with SM capacitors. Why use a silvered mica capacitor in an preamp when a Mylar one can do, with one tenth of the cost?

    Usually Mylar capacitor are green but i have also seen brown and occasionally the color shown in the photo posted above.
     
Loading...