Hi everyone, I'm getting my two BA-2 back on the workbench to check for some minor hum that is probably as loud as the preamp self noise. It might be caused by a non optimal placement of a 230V-110V step down transformer. But testing seems strange:
My issue is that I'm confused on how to test the hum properly. I tried it with a 150 ohm XLR plug, but it seems to behave differently than a mic. Also, line level fed from the interface makes the hum type change (not reacting to the transformer placement at all). It feels like there are too many variables and I can't come to any conclusions. Sometimes the hum changes with moving the step down transformer, with other constellations it doesn't.
What's the proper feed to test the noise of a BA-2?
My issue is that I'm confused on how to test the hum properly. I tried it with a 150 ohm XLR plug, but it seems to behave differently than a mic. Also, line level fed from the interface makes the hum type change (not reacting to the transformer placement at all). It feels like there are too many variables and I can't come to any conclusions. Sometimes the hum changes with moving the step down transformer, with other constellations it doesn't.
What's the proper feed to test the noise of a BA-2?
