Grubb
Well-known member
I built a crazy bass pedal for a work colleague's band earlier this year and it has been working for them until recently. It has a fuzz, boost and filter inside it, all living on separate circuit boards. You can see more about it if you are interested on this page: Bass fuzz/filter
It has been returned to me for a repair as it has recently stopped filtering properly. Fuzz, boost and switching all work as expected. The filter circuit passes audio but the filter effect is not present at the output. I used my audio probe to trace the circuit and think I have located possible issues, but I just need some advice on what the problem is.
**EDIT: I altered the PCB file on my computer after I had this PCB fabricated, and subsequently I probed a couple of places incorrectly. The schematic has been updated. After checking, the fault seems to be at IC2 Pin 2 and the associated network. When I touch the probe to that net, all signal disappears, including all hum.
It has been returned to me for a repair as it has recently stopped filtering properly. Fuzz, boost and switching all work as expected. The filter circuit passes audio but the filter effect is not present at the output. I used my audio probe to trace the circuit and think I have located possible issues, but I just need some advice on what the problem is.
**EDIT: I altered the PCB file on my computer after I had this PCB fabricated, and subsequently I probed a couple of places incorrectly. The schematic has been updated. After checking, the fault seems to be at IC2 Pin 2 and the associated network. When I touch the probe to that net, all signal disappears, including all hum.
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