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