New
#11
If you have a cheap "sacrificial power bar" you can connect them on it and remove the ground from that instead, for your test.
Most of the time it's what I do... I've been installing audio stuff since 40 years, and at least 3-4% of installations have that kind of hack... No one chasing me because he's business burned or someone got electrocuted... and I can tell that in a city mall "0" audio stuff is grounded... it's all one pair, all the way.
If you still get that buzzing sound... It could be your Video card that is interfering with other component in your computer... But I rather not think about that now...
I lately learned that even grounding high power LED flood lights was not always a good thing too, $$$$... Even if there's a ground lead coming out.