Jog won't work when connected to my amp

Hello everyone!

I recently set up my home DJ setup with a DDJ-GRV6, but I'm having an issue that makes it impossible to mix properly.

I've done a lot of troubleshooting (tried powering the Mac and GRV6 in different ways, changed RCA cables, tried 6.3 mm jack-to-RCA cables, bought a ground loop isolator, etc.), but the issue persists.

Whenever the GRV6 is connected to my amplifier (Fosi Audio BT30D), the jog wheels stop detecting touch. I also tested the audio output from my Mac through a jack-to-RCA cable, and the same thing happens.

If the amp is turned off, the jog wheels work perfectly. But obviously, I can't mix with the amp turned off!

As soon as I turn the amp on, the capacitive touch detection stops working on both jog wheels.

I've already had to replace my first Fosi BT30D because it was faulty and had other issues, so I'm wondering if this could be related to the amp or its power supply.

I've tried a ground loop isolator as well, but it didn't solve the problem and introduced some crackling noise.

Has anyone experienced a similar issue or found a solution? I'd really appreciate any suggestions!

I'm also contacting Fosi Audio about this.

Thanks in advance ^^