Rock-Ola 56180-1A amp from an Antique Apparatus/Rock-Ola OMT type.
This amp had a crackle/rumble on 1 channel with the volume down all the
way. Traced it to a tantalum cap with leakage. After replacing it, I
could then hear that the other channel had the same problem so I
replaced it (I used electrolytic caps, which I didn't think will be a
problem) I don't stock any tantalum caps. (yet)
Then at the end of a song before it was muted, I heard a very slight
crackle, much less but I heard it. While it was playing I pulled the CD
inputs and when turning up the volume the noise was louder with the
volume up. The amp is loaded with 1uF tantalum caps and I'm wondering if
there was a bad batch and I should replace them all.
Now I did a search and find that John Robertson here had changed the
same two as me (C12,C13) and two more (C6,C7). John, if you recall, are
C6 and C7 before the volume control? My AMR manual schematic is really
poor and I can hardly read the part values, does anyone have a factory
one and is it much better?
Tony
