SOLVED! All the legs on the old IR3109 weren’t making reliable contact into the socket (maybe they made them thinner back then?) – I put some flux on the legs then dabbed on a bit of solder to make them thicker, then jammed it into the socket. Works great now!
Just finished building IR3109 filter and I can’t get any sound out at all (yes I jumped R1 and R2). The control board is fine, works great with other filters. IR3109 is from Ebay, advertised as verified to be working. I have -5V at VEE and +5V at VCC on pins 8 and 16. I selected lpf as the filter type and also tried all other filter types and scrolled through all the presets. No sound whatsoever.
What else should I check to verify that this is a working IR3109 chip?
This is the 4th filter I’ve built and I’ve yet to have any issue with audio output. I even tried it with 2 different control boards. I suspect the IR3109 isn’t actually working but I have no idea how to test it.