T4S hum in headset during rehearsal

Portable PA
1

When running SM58 mike in channel #1 and acoustic guitar with onboard blender (a Fishman Prefix in channel #2 or LR Baggs Stage Pro Anthem in channel #3), and using a headset for rehearsal with neither of two L1's connected, I get a hum in the headphones that goes away when my lips touch the mike. Running no main volume, almost maxed out trims (occasional red flicker) and 1 o'clock channel levels. Feels like I need to ground the rig, but if so, how? Thanks!

2

Hi Wonder,

 

I advise we attempt some troubleshoot here. Check out the below steps:

  • Is the humming present when using other headphones?
  • Have you tried using a different Mic to test?
  • Does the humming continue if we use a different XLR Cable from the Mic? 

Hopefully one of the above steps will isolate the issue.

 

Let me know how it goes!

3

Thanks for suggested diagnostic pathway. I tried taking the AC protector strip out of the 110VAC feed to the T4S power supply. Muchmost of hum went away. If it continues I'll look using your scheme. Many thanks.

 

Wonder