I've got a tough one for any troubleshooting gurus on here (or hopefully the SA folks will weigh in). On my board I've got 5 SA pedals (Atlas, C4, Aftershock, Gemini, EQ2) and a neuro hub (as well as a kliq tuner and a midi mouse). I have been using a cheap Amazon power supply (Caline CP-202) without issue. A couple of weeks ago, when I added the Gemini to my board, I started getting some horrible noise issues. A ringing sound that the noise filter could take care of, but as soon as i start playing it is very pronounced and annoying.
So my initial thought is the power supply. I drop the cash and test with a good quality isolated supply (1-Spot CS7) without changing anything else, no change. So now I've completely torn my board apart and have been stepping slowly through troubleshooting. Here is what I've found:
1. The EQ2 seemed to be having a problem with the cheap power supply. I started adding pedals and as soon as i got the EQ2 in place, the ringing noise came back. At this point, I have not added the hub or midi mouse back in. So, I swap in the CS-7, and the noise goes away. Eureka! I think that the issue is the cheap power supply not providing current to EQ2 (and I don't think it's actually isolated, despite what they've screen printed on it). but....
2. Before rebuilding my board, I want to make sure that everything still works once adding the neuro hub and midi mouse back in. Once i plug the neuro hub in with a trrs cable to each pedal, the noise is back! Now I'm annoyed, as this is with the new power supply. So more troubleshooting, and I find that when I unplug the trrs cable from the EQ2, the ringing instantly stops. This does not happen when unplugging it from any of the other pedals. I did test a different cable and a different output on the hub with the EQ2, and still, the ringing is back as soon as I plug in the trrs. Note that i also tested with the EQ2 plugged into the original SA power supply, just in case.
So at this point, I'm reasonably confident that I had a power supply issue, but there still is an issue with either the neuro hub or the EQ2. Any ideas?