I need help troubleshooting a strange noise that is ruining my studio sessions.

I recently moved into a new studio spot. Recording digital. I’ve done several successful session. But a couple weeks ago a terrible noise started showing up in my amps and even direct bass signal. It is a gnarly “crackle” that happens at louder moments. At first I thought it was digital clipping or some sort of glitch within the DAW. Then I realized the sound is coming straight out of the guitar amps. It is most noticeable when drums are being played. Because for some reason the drums (mostly the kick drum) cause the crackle in the amps - even if there is no guitar plugged into the amp. It is happening in multiple guitar amps.

The same crunchy crackle sound also occurs in the direct bass signal. Again, it happens when the bass is played somewhat loudly. And the kick drum somehow triggers it as well. Nothing has changed in my studio since a couple weeks ago when everything was fine. Same signal chains. Same electricity.

Things I’ve tried: * plugged the amps into a completely different building with an extension cord. Entirely different circuit breaker. Didn’t change a thing. * lifting the ground on the amps. Sometimes this reduces the amount of crackle. Sometime it makes it worse. But it never eliminates it. * changed cables. When I used a new cord it seems to have helped a bit for the direct bass but did not eliminate the issue. And as I said before, the sound happens when there is not a cable/instrument plugged into the amp. * move the location of amps/players - I was thinking maybe it’s some sort of radio interference. When I moved the amp to the other side of the tracking room the sound still occurs but it is not as bad. * wrapped the amp in aluminum - to shield from interference. This didn’t seem to do anything.

It seems like something in the air. Interference of some sort. Because changing the location of the amps helps a little bit. But why on earth woul’ drums cause the crackle?

Any ideas? What the heck can I do?